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Ôn luyện hóa hữu cơ 12 cực hay có lời giải (Đề số 02)

Thủy phân hoàn toàn H2N-CH2-CO-NH-CH(CH3)-CO-NH-CH(CH3)-CO-NH-CH2-CO-NH-CH2-COOH  thu được bao nhiêu loại α-amino axit khác nhau ?

Hóa học Lớp 12
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900 bài ôn tập rèn luyện lý thuyết tổng hợp môn hóa học (P11)

Cho các phương trình phản ứng hoá học sau (các phản ứng đều ở điều kiện thường và xúc tác thích hợp):Phát biểu nào sau đây là sai:

Hóa học Lớp 12
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Ôn luyện hóa hữu cơ 12 cực hay có lời giải (Đề số 02)

Thủy phân hoàn toàn 0,1 mol peptit Ala-Gly-Ala trong 400 ml dung dịch NaOH 1,0M. Khối lượng chất rắn thu được khi cô cạn dung dịch sau phản ứng là :

Hóa học Lớp 12
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Đề luyện thi THPT Quốc Gia - Năm 2020 Môn thi: TIẾNG ANH (Đề số 1)

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 35 to 42.Biological diversity has become widely recognized as a critical conservation issue only in the past two decades. The rapid destruction of the tropical rain forests, which are the ecosystems with the highest known species diversity on Earth, has awakened people to the importance and fragility of biological diversity. The high rate of species extinctions in these environments is jolting, but it is important to recognize the significance of biological diversity in all ecosystems. As the human population continues to expand, it will negatively affect one after another of Earth's ecosystems. In terrestrial ecosystems and in fringe marine eco common problem is habitat destruction. In most situations, the result is irreversible. Now humans are beginning to destroy marine ecosystems through other types of activities, such as disposal and runoff of poisonous waste; in less than two centuries, by significantly reducing the variety of species on Earth, they have irrevocably redirected the course of evolution. Certainly, there have been periods in Earth's history when mass extinctions have occurred. The extinction of the dinosaurs was caused by some physical event, either climatic or cosmic. There have also been less dramatic extinctions, as when natural competition between species reached an extreme conclusion. Only 0.01 percent of the species that have lived on Earth have survived to the present, and it was largely chance that determined which species survived and which died out. However, nothing has ever equaled the magnitude and speed with which the human species is altering the physical and chemical world and demolishing the environment. In fact, there is wide agreement that it is the rate of change humans are inflicting, even more than the changes themselves that will lead to biological devastation. Life on Earth has continually been in flux as slow physical and chemical changes have occurred on Earth, but life needs time to adapt-time for migration and genetic adaptation within existing species and time for the proliferation of new genetic material and new species that may be able to survive in new environments.The author mentions all of the following as examples of the effect of humans on the world's ecosystems EXEPT ______ .

Tiếng Anh Tốt nghiệp THPT
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900 bài ôn tập rèn luyện lý thuyết tổng hợp môn hóa học (P11)

Thực hiện các thí nghiệm sau:(1) Thả một đinh Fe vào dung dịch HCl.(2) Thả một đinh Fe vào dung dịch Ni(NO3)2.(3) Thả một đinh Fe vào dung dịch FeCl3.(4) Nối một dây Fe với một dây Cu rồi để trong không khí ẩm.(5) Đốt một dây Fe trong bình kín chỉ chứa đầy khí O2.(6) Thả một đinh Fe vào dung dịch chứa CuSO4 và H2SO4 loãng. Trong các thí nghiệm trên thì các thí nghiệm mà Fe bị ăn mòn điện hoá học là:

Hóa học Lớp 12
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Bài kiểm tra số 3

Đốt cháy hoàn toàn 8,7 gam amino axit X (có một nhóm NH2) thì thu được 0,3 mol CO2; 0,25 mol H2O và 1,12 lít (ở đktc) một khí trơ. Công thức phân tử của X là:

Hóa học Lớp 12
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Ôn luyện hóa hữu cơ 12 cực hay có lời giải (Đề số 02)

Câu 10: Câu 10: 00021Cho 1,52 gam hỗn hợp hai amin no, đơn chức X và Y (có số mol bằng nhau) tác dụng vừa đủ với 200 ml dung dịch HCl, thu được 2,98 gam muối. Kết luận nào sau đây không chính xác ?

Hóa học Lớp 12
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900 bài ôn tập rèn luyện lý thuyết tổng hợp môn hóa học (P11)

Cho các este: etyl format (1), vinyl axetat (2), triolein (3), metyl acrylat (4), phenyl axetat (5). Dãy gồm các este đều phản ứng được với dung dịch NaOH (đun nóng) sinh ra ancol là

Hóa học Lớp 12
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Ôn luyện hóa hữu cơ 12 cực hay có lời giải (Đề số 02)

Khi nấu canh cua thì thấy các mảng “riêu cua” nổi lên là do :

Hóa học Lớp 12
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Bài kiểm tra số 3

Đốt cháy hoàn toàn a mol một amino axit X bằng lượng oxi vừa đủ rồi làm lạnh để ngưng tụ hơi nước thu được 2,5a mol hỗn hợp khí. Công thức phân tử của X là:

Hóa học Lớp 12
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Bài kiểm tra số 3

Este X tạo thành từ amino axit và ancol etylic. Đốt cháy hoàn toàn 10,3 gam X thu được 17,6 gam khí CO2, 8,1 gam H2O và 1,12 lit N2 (đktc). Amino axit tạo thành X là

Hóa học Lớp 12
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Ôn luyện hóa hữu cơ 12 cực hay có lời giải (Đề số 02)

Tripanmitin có công thức là

Hóa học Lớp 12
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Ôn luyện hóa hữu cơ 12 cực hay có lời giải (Đề số 02)

Cho 8,88 gam chất chứa nhân thơm X có công thức C2H3OOCC6H3(OH)OOCCH3 vào 200 ml KOH 0,9M đun nóng đến phản ứng hoàn toàn, thu được dung dịch B. Cô cạn B thu được b gam chất rắn khan. Giá trị của b là

Hóa học Lớp 12
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Đề luyện thi THPT Quốc Gia - Năm 2020 Môn thi: TIẾNG ANH (Đề số 1)

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 30 to 34.Humans generally spent more time working than do other creatures, but there is greater variability in industriousness from one human culture to the next than is seen in subgroups of any other species. For instance, the average French worker toils for 1,646 hours a year; the average American for 1,957 hours; and the average Japanese for 2,088. One reason for human diligence is that people, unlike animals, can often override the impulses they may feel to slow down. They can drink coffee when they might prefer a nap or flick on the air-conditioning when the heat might otherwise demand torpor. Many humans are driven to work hard by a singular desire to gather resources far beyond what is required for survival. Squirrels may collect what they need to make it through one winter but only humans worry about collect bills, retirement, or replacing their old record albums with compact discs. Among other primates, if you don't need to travel around to get food for that day, you sit down and relax, said Dr.Frans de Waal of Emory University in Atlarita. "it's typically human to try to accumulate wealth and get more and more.” Much of the acquisitiveness is likely to be the result of cultural training. Anthropologists have found that most hunter-gatherer groups, who live day to day on the resources they can kill or forage and who stash very little away for the future generally work only three to five hours daily. Indeed, an inborn temptation to reduce may lurk beneath even the most work-obsessed people, which could explain why sloth ranks with lust and gluttony as one of the seven deadly sins.The passage is a combination of contrast and _______ .

Tiếng Anh Tốt nghiệp THPT
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Ôn luyện hóa hữu cơ 12 cực hay có lời giải (Đề số 02)

Tơ nitron (olon) là sản phẩm trùng hợp của monome nào sau đây?

Hóa học Lớp 12
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Bài kiểm tra số 3

Cho m gam valin vào 200 ml dung dịch HCl 1M, dung dịch sau phản ứng tác dụng vừa đủ với 250 ml NaOH 2M. Mặc khác, nếu đốt cháy m gam valin thì cần V lít khí O2 (đktc). Giá trị V là:

Hóa học Lớp 12
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Bài kiểm tra số 3

Cho m gam hỗn hợp X gồm glixin và alanin tác dụng với dung dịch NaOH vừa đủ thu được (m+11) gam muối. Nếu đốt cháy hoàn toàn m gam hỗn hợp X thì cần 35,28 lít O2 (đktc). Giá trị của m là 

Hóa học Lớp 12
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Bài kiểm tra số 3

Cho 13,35 gam hỗn hợp X gồm (NH2CH2CH2COOH và CH3CHNH2COOH) tác dụng với V ml dung dịch NaOH 1 M thu được dung dịch Y. Biết dung dịch Y tác dụng vừa đủ với 250 ml dung dịch HCl 1M. Giá trị của V là 

Hóa học Lớp 12
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20 BỘ ĐỀ THI THỬ THPT QUỐC GIA LẦN 1 NĂM HỌC 2018 - 2019 MÔN: TIẾNG ANH(ĐỀ 8)

Mark the letter A, B, C or D on your answer sheet to indicate the sentence that is closest in meaning to each of the following questions from 48 to 50.She had to buy a new battery for her mobile phone because the charge was unable to last for more than two hours.

Tiếng Anh Tốt nghiệp THPT
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Đề luyện thi THPT Quốc Gia - Năm 2020 Môn thi: TIẾNG ANH (Đề số 1)

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 30 to 34.Humans generally spent more time working than do other creatures, but there is greater variability in industriousness from one human culture to the next than is seen in subgroups of any other species. For instance, the average French worker toils for 1,646 hours a year; the average American for 1,957 hours; and the average Japanese for 2,088. One reason for human diligence is that people, unlike animals, can often override the impulses they may feel to slow down. They can drink coffee when they might prefer a nap or flick on the air-conditioning when the heat might otherwise demand torpor. Many humans are driven to work hard by a singular desire to gather resources far beyond what is required for survival. Squirrels may collect what they need to make it through one winter but only humans worry about collect bills, retirement, or replacing their old record albums with compact discs. Among other primates, if you don't need to travel around to get food for that day, you sit down and relax, said Dr.Frans de Waal of Emory University in Atlarita. "it's typically human to try to accumulate wealth and get more and more.” Much of the acquisitiveness is likely to be the result of cultural training. Anthropologists have found that most hunter-gatherer groups, who live day to day on the resources they can kill or forage and who stash very little away for the future generally work only three to five hours daily. Indeed, an inborn temptation to reduce may lurk beneath even the most work-obsessed people, which could explain why sloth ranks with lust and gluttony as one of the seven deadly sins.What does the word “They” in paragraph 2 refers to?

Tiếng Anh Tốt nghiệp THPT
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20 BỘ ĐỀ THI THỬ THPT QUỐC GIA LẦN 1 NĂM HỌC 2018 - 2019 MÔN: TIẾNG ANH(ĐỀ 8)

Mark the letter A, B, C or D on your answer sheet to indicate the sentence that is closest in meaning to each of the following questions from 48 to 50. After the members of the committee had had lunch, they discussed the problem.

Tiếng Anh Tốt nghiệp THPT
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Bài kiểm tra số 3

Một amino axit X chỉ chứa một chức -NH2 và một chức -COOH. Cho m gam X tác dụng với 300 ml dung dịch HCl 1M thu được dung dịch Y. Dung dịch Y phản ứng vừa đủ với 500 ml dung dịch NaOH 1M và thu được dung dịch Z. Cô cạn dung dịch Z thu được 39,75 gam muối khan. Amino axit X là:

Hóa học Lớp 12
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20 BỘ ĐỀ THI THỬ THPT QUỐC GIA LẦN 1 NĂM HỌC 2018 - 2019 MÔN: TIẾNG ANH(ĐỀ 8)

Mark the letter A, B, C or D on your answer sheet to indicate the sentence that is closest in meaning to each of the following questions from 48 to 50.A child is influenced as much by his schooling as by his parents.

Tiếng Anh Tốt nghiệp THPT
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30 đề luyện thi Đại Học môn Tiếng Anh cực hay có lời giải (Đề số 23)

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questionsThe biologist's role in society as well as his moral and ethical responsibility in the discovery and development of new ideas has led to a reassessment of his social and scientific value systems. A scientist can no longer ignore the consequences of his discoveries; he is as concerned with the possible misuses of his findings as he is with the basic research in which he is involved. This emerging social and political role of the biologist and all other scientists requires a weighing of values that cannot be done with the accuracy or the objectivity of a laboratory balance. As a member of society, it is necessary for a biologist now to redefine his social obligations and his functions, particularly in the realm of making judgments about such ethical problems as man's control of his environment or his manipulation of genes to direct further evolutionary development.As a result of recent discoveries concerning hereditary mechanisms, genetic engineering, by which human traits are made to order, may soon be a reality. As desirable as it_may seem to be, such an accomplishment would entail many value judgments. Who would decide, for example, which traits should be selected for change? In cases of genetic deficiencies and disease, the desirability of the change is obvious, but the possibilities for social misuse are so numerous that they may far outweigh the benefits.Probably the greatest biological problem of the future, as it is of the present, will be to find ways to curb environmental pollution without interfering with man's constant effort to improve the quality of his life. Many scientists believe that underlying the spectre of pollution is the problem of surplus human population. A rise in population necessitates an increase in the operations of modern industry, the waste products of which increase the pollution of air, water, and soil. The question of how many people the resources of the Earth can support is one of critical importance.       Although the solutions to these and many other problems are yet to be found, they do indicate the need for biologists to work with social scientists and other members of society in order to determine the requirements necessary for maintaining a healthy and productive planet. For although many of man's present and future problems may seem to be essentially social, political, or economic in nature, they have biological ramifications that could affect the very existence of life itself.It is implied in the passage that genetic engineering __________. 

Tiếng Anh Tốt nghiệp THPT
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Bài kiểm tra số 3

Amino axit X chứa a nhóm –COOH và b nhóm –NH2. Cho 1 mol X tác dụng hết với dung dịch HCl thu được 169,5 gam muối. Cho 1 mol X tác dụng hết với dung dịch NaOH thì thu được 177 gam muối. Công thức phân tử của X là:

Hóa học Lớp 12
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Tổng hợp đề thi Tiếng Anh có lời giải (Đề số 10)

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 35 to 44Here are tips that help succeed in your job interview:Always arrive early. If you do not know (35) ______ the organization is located, call for exact directions (36) ______ advance. Leave some extra time for any traffic, parking, or (37) ______ events. If you are running late, call right away and let someone know. The best time to arrive is approximately 5 - 10 minutes early. Give (38) ______ the time to read your resume one more time, to catch your breath, and to be ready for the interview. Once you are at the office, treat everyone you encounter with respect. Be (39) ______ to everyone as soon as you walk in the door.Wear a professional business suit. This point should be emphasized enough. First (40) ______ are extremely important in the interview process. Women should (41) ______ wearing too much jewelry or make up. Men should avoid flashy suits or wearing too much perfume. It is (42) ______ important that you feel comfortable. While a suit is the standard interview attire in a business environment, if you think it is (43) ______ informal environment, call before and ask. Regardless, you can never be overdressed (44) ______ you are wearing a tailored suit.Question 37

Tiếng Anh Tốt nghiệp THPT
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20 BỘ ĐỀ THI THỬ THPT QUỐC GIA LẦN 1 NĂM HỌC 2018 - 2019 MÔN: TIẾNG ANH(ĐỀ 8)

Mark the letter A, B, C or D on your answer sheet to indicate the underlined part that needs correction in each of the following questions from 45 to 47.The 1983 Nobel Prize in Medicine was awarded to Barbara McClintock for her experiments with maize and her discoveries regardless the nature of DNA.

Tiếng Anh Tốt nghiệp THPT
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Ôn luyện hóa hữu cơ 12 cực hay có lời giải (Đề số 02)

Thuỷ phân hoàn toàn glixerol trifomiat trong 200 gam dung dịch NaOH cô cạn dung dịch hỗn hợp sau phản ứng thu được 28,4 gam chất rắn khan và 9,2 gam ancol. Xác định nồng độ phần trăm của dung dịch NaOH?

Hóa học Lớp 12
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20 BỘ ĐỀ THI THỬ THPT QUỐC GIA LẦN 1 NĂM HỌC 2018 - 2019 MÔN: TIẾNG ANH(ĐỀ 8)

Mark the letter A, B, C or D on your answer sheet to indicate the underlined part that needs correction in each of the following questions from 45 to 47.When a pearl is cut in half and examined under a microscope, but its layers can be seen.

Tiếng Anh Tốt nghiệp THPT
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Bài kiểm tra số 3

Cho 0,01 mol một amino axit X tác dụng vừa hết với 80ml dung dịch HCl 0,125M được dung dịch Y. Dung dịch Y tác dụng vừa hết với 300ml dung dịch NaOH 0,1M được dung dịch Z. Cô cạn Z được 2,835 gam chất rắn khan. X là: 

Hóa học Lớp 12
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Tổng hợp đề thi Tiếng Anh có lời giải (Đề số 10)

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 35 to 44Here are tips that help succeed in your job interview:Always arrive early. If you do not know (35) ______ the organization is located, call for exact directions (36) ______ advance. Leave some extra time for any traffic, parking, or (37) ______ events. If you are running late, call right away and let someone know. The best time to arrive is approximately 5 - 10 minutes early. Give (38) ______ the time to read your resume one more time, to catch your breath, and to be ready for the interview. Once you are at the office, treat everyone you encounter with respect. Be (39) ______ to everyone as soon as you walk in the door.Wear a professional business suit. This point should be emphasized enough. First (40) ______ are extremely important in the interview process. Women should (41) ______ wearing too much jewelry or make up. Men should avoid flashy suits or wearing too much perfume. It is (42) ______ important that you feel comfortable. While a suit is the standard interview attire in a business environment, if you think it is (43) ______ informal environment, call before and ask. Regardless, you can never be overdressed (44) ______ you are wearing a tailored suit.Question 36

Tiếng Anh Tốt nghiệp THPT
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20 BỘ ĐỀ THI THỬ THPT QUỐC GIA LẦN 1 NĂM HỌC 2018 - 2019 MÔN: TIẾNG ANH(ĐỀ 8)

Mark the letter A, B, C or D on your answer sheet to indicate the underlined part that needs correction in each of the following questions from 45 to 47.The plant leaf has vascular tissues just as the stem and the root does.

Tiếng Anh Tốt nghiệp THPT
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Ôn luyện hóa hữu cơ 12 cực hay có lời giải (Đề số 02)

Cho 9 gam chất hữu cơ A có công thức CH4ON2 phản ứng hoàn toàn với 450 ml dung dịch NaOH 1M, giải phóng khí NH3. Cô cạn dung dịch sau phản ứng thu được m gam chất rắn khan. Giá trị của m là:

Hóa học Lớp 12
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Đề luyện thi THPT Quốc Gia - Năm 2020 Môn thi: TIẾNG ANH (Đề số 1)

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 30 to 34.Humans generally spent more time working than do other creatures, but there is greater variability in industriousness from one human culture to the next than is seen in subgroups of any other species. For instance, the average French worker toils for 1,646 hours a year; the average American for 1,957 hours; and the average Japanese for 2,088. One reason for human diligence is that people, unlike animals, can often override the impulses they may feel to slow down. They can drink coffee when they might prefer a nap or flick on the air-conditioning when the heat might otherwise demand torpor. Many humans are driven to work hard by a singular desire to gather resources far beyond what is required for survival. Squirrels may collect what they need to make it through one winter but only humans worry about collect bills, retirement, or replacing their old record albums with compact discs. Among other primates, if you don't need to travel around to get food for that day, you sit down and relax, said Dr.Frans de Waal of Emory University in Atlarita. "it's typically human to try to accumulate wealth and get more and more.” Much of the acquisitiveness is likely to be the result of cultural training. Anthropologists have found that most hunter-gatherer groups, who live day to day on the resources they can kill or forage and who stash very little away for the future generally work only three to five hours daily. Indeed, an inborn temptation to reduce may lurk beneath even the most work-obsessed people, which could explain why sloth ranks with lust and gluttony as one of the seven deadly sins.The word “torpor” in paragraph 2 mostly means _____ .

Tiếng Anh Tốt nghiệp THPT
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Tổng hợp đề thi Tiếng Anh có lời giải (Đề số 10)

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 35 to 44Here are tips that help succeed in your job interview:Always arrive early. If you do not know (35) ______ the organization is located, call for exact directions (36) ______ advance. Leave some extra time for any traffic, parking, or (37) ______ events. If you are running late, call right away and let someone know. The best time to arrive is approximately 5 - 10 minutes early. Give (38) ______ the time to read your resume one more time, to catch your breath, and to be ready for the interview. Once you are at the office, treat everyone you encounter with respect. Be (39) ______ to everyone as soon as you walk in the door.Wear a professional business suit. This point should be emphasized enough. First (40) ______ are extremely important in the interview process. Women should (41) ______ wearing too much jewelry or make up. Men should avoid flashy suits or wearing too much perfume. It is (42) ______ important that you feel comfortable. While a suit is the standard interview attire in a business environment, if you think it is (43) ______ informal environment, call before and ask. Regardless, you can never be overdressed (44) ______ you are wearing a tailored suit.Question 35

Tiếng Anh Tốt nghiệp THPT
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20 BỘ ĐỀ THI THỬ THPT QUỐC GIA LẦN 1 NĂM HỌC 2018 - 2019 MÔN: TIẾNG ANH(ĐỀ 8)

Mark the letter A, B, C or D on your answer sheet to indicate the word(s) CLOSEST in meaning to the underlined word(s) in each of the following questions from 43 to 44.The giraffe is conspicuous in the grasslands because of its long neck.

Tiếng Anh Tốt nghiệp THPT
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20 BỘ ĐỀ THI THỬ THPT QUỐC GIA LẦN 1 NĂM HỌC 2018 - 2019 MÔN: TIẾNG ANH(ĐỀ 8)

Mark the letter A, B, C or D on your answer sheet to indicate the word(s) CLOSEST in meaning to the underlined word(s) in each of the following questions from 43 to 44.Many parents may fail to recognize and respond to their children's needs until frustration explodes into difficult or uncooperative behaviour.

Tiếng Anh Tốt nghiệp THPT
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Ôn luyện hóa hữu cơ 12 cực hay có lời giải (Đề số 02)

Đốt cháy hoàn toàn hỗn hợp X gồm: axit axetic, etyl axetat, metyl axetat rồi cho toàn bộ sản phẩm cháy vào bình (1) đựng dung dịch H2SO4 đặc, dư; bình (2) đựng Ba(OH)2 dư. Kết thúc thí nghiệm thấy bình (1) tăng thêm m gam, bình (2) thu được 10,835 gam kết tủa. Giá trị của m là

Hóa học Lớp 12
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20 BỘ ĐỀ THI THỬ THPT QUỐC GIA LẦN 1 NĂM HỌC 2018 - 2019 MÔN: TIẾNG ANH(ĐỀ 8)

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 38 to 42. Fill in the appropriate word in question 42        The popular image of student life is of young people with few responsibilities enjoying themselves and (38) _____ very little work. This is often not true. Many older people now study at college or university, sometimes (39) _____ a part-time basis while having a job and looking after a family. These students are often highly motivated and work very hard.        Younger students are often thought to be lazy and careless about money (40) _____ this situation is changing. In Britain reduced government support for higher education means that students can no longer rely on having their expenses paid for them. Formerly, students received a grant towards their living expenses. Now most can only get a loan (41) _____ has to be paid back. Since 1999 they have paid over £1,000 towards tuition fees and this amount will increase up to a maximum of £3,000. In the US students already have to pay for tuition and room and board.        Many get a financial aid package which may include grants, scholarships and loans. The fear of having large debts places (42) _____ pressure on students and many take part-time jobs during the term and work full-time in the vacations.

Tiếng Anh Tốt nghiệp THPT
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Đề luyện thi THPT Quốc Gia - Năm 2020 Môn thi: TIẾNG ANH (Đề số 1)

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 30 to 34.Humans generally spent more time working than do other creatures, but there is greater variability in industriousness from one human culture to the next than is seen in subgroups of any other species. For instance, the average French worker toils for 1,646 hours a year; the average American for 1,957 hours; and the average Japanese for 2,088. One reason for human diligence is that people, unlike animals, can often override the impulses they may feel to slow down. They can drink coffee when they might prefer a nap or flick on the air-conditioning when the heat might otherwise demand torpor. Many humans are driven to work hard by a singular desire to gather resources far beyond what is required for survival. Squirrels may collect what they need to make it through one winter but only humans worry about collect bills, retirement, or replacing their old record albums with compact discs. Among other primates, if you don't need to travel around to get food for that day, you sit down and relax, said Dr.Frans de Waal of Emory University in Atlarita. "it's typically human to try to accumulate wealth and get more and more.” Much of the acquisitiveness is likely to be the result of cultural training. Anthropologists have found that most hunter-gatherer groups, who live day to day on the resources they can kill or forage and who stash very little away for the future generally work only three to five hours daily. Indeed, an inborn temptation to reduce may lurk beneath even the most work-obsessed people, which could explain why sloth ranks with lust and gluttony as one of the seven deadly sins.According to the author, humans are so industrious because ______ 

Tiếng Anh Tốt nghiệp THPT
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Ôn luyện hóa hữu cơ 12 cực hay có lời giải (Đề số 02)

Thủy phân este có công thức phân tử C4H8O2 (với xúc tác axit), thu được 2 sản phẩm hữu cơ X và Y. Từ X có thể điều chế trực tiếp ra Y. Vậy chất X là:

Hóa học Lớp 12
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30 đề luyện thi Đại Học môn Tiếng Anh cực hay có lời giải (Đề số 23)

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questionsThe biologist's role in society as well as his moral and ethical responsibility in the discovery and development of new ideas has led to a reassessment of his social and scientific value systems. A scientist can no longer ignore the consequences of his discoveries; he is as concerned with the possible misuses of his findings as he is with the basic research in which he is involved. This emerging social and political role of the biologist and all other scientists requires a weighing of values that cannot be done with the accuracy or the objectivity of a laboratory balance. As a member of society, it is necessary for a biologist now to redefine his social obligations and his functions, particularly in the realm of making judgments about such ethical problems as man's control of his environment or his manipulation of genes to direct further evolutionary development.As a result of recent discoveries concerning hereditary mechanisms, genetic engineering, by which human traits are made to order, may soon be a reality. As desirable as it_may seem to be, such an accomplishment would entail many value judgments. Who would decide, for example, which traits should be selected for change? In cases of genetic deficiencies and disease, the desirability of the change is obvious, but the possibilities for social misuse are so numerous that they may far outweigh the benefits.Probably the greatest biological problem of the future, as it is of the present, will be to find ways to curb environmental pollution without interfering with man's constant effort to improve the quality of his life. Many scientists believe that underlying the spectre of pollution is the problem of surplus human population. A rise in population necessitates an increase in the operations of modern industry, the waste products of which increase the pollution of air, water, and soil. The question of how many people the resources of the Earth can support is one of critical importance.       Although the solutions to these and many other problems are yet to be found, they do indicate the need for biologists to work with social scientists and other members of society in order to determine the requirements necessary for maintaining a healthy and productive planet. For although many of man's present and future problems may seem to be essentially social, political, or economic in nature, they have biological ramifications that could affect the very existence of life itself.The pronoun "it" in paragraph 2 refers to__________.

Tiếng Anh Tốt nghiệp THPT
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20 BỘ ĐỀ THI THỬ THPT QUỐC GIA LẦN 1 NĂM HỌC 2018 - 2019 MÔN: TIẾNG ANH(ĐỀ 8)

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 38 to 42. Fill in the appropriate word in question 41        The popular image of student life is of young people with few responsibilities enjoying themselves and (38) _____ very little work. This is often not true. Many older people now study at college or university, sometimes (39) _____ a part-time basis while having a job and looking after a family. These students are often highly motivated and work very hard.        Younger students are often thought to be lazy and careless about money (40) _____ this situation is changing. In Britain reduced government support for higher education means that students can no longer rely on having their expenses paid for them. Formerly, students received a grant towards their living expenses. Now most can only get a loan (41) _____ has to be paid back. Since 1999 they have paid over £1,000 towards tuition fees and this amount will increase up to a maximum of £3,000. In the US students already have to pay for tuition and room and board.        Many get a financial aid package which may include grants, scholarships and loans. The fear of having large debts places (42) _____ pressure on students and many take part-time jobs during the term and work full-time in the vacations.

Tiếng Anh Tốt nghiệp THPT
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Ôn luyện hóa hữu cơ 12 cực hay có lời giải (Đề số 02)

Thủy phân hợp chất sau (hợp chất X) thì thu được bao nhiêu loại amino axit ?

Hóa học Lớp 12
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Bài kiểm tra số 3

Cho m gam hh X gồm axit glutamic và alanin t/d với dd HCl dư. Sau pứ làm bay hơi cẩn thận dd thu được (m + 11,68) gam muối khan. Nếu cho m gam hh X t/d với dd KOH vừa đủ, sau pứ làm bay hơi cẩn thận dd thu được (m + 19) gam muối khan. Giá trị của m là:

Hóa học Lớp 12
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20 BỘ ĐỀ THI THỬ THPT QUỐC GIA LẦN 1 NĂM HỌC 2018 - 2019 MÔN: TIẾNG ANH(ĐỀ 8)

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 38 to 42. Fill in the appropriate word in question 40        The popular image of student life is of young people with few responsibilities enjoying themselves and (38) _____ very little work. This is often not true. Many older people now study at college or university, sometimes (39) _____ a part-time basis while having a job and looking after a family. These students are often highly motivated and work very hard.        Younger students are often thought to be lazy and careless about money (40) _____ this situation is changing. In Britain reduced government support for higher education means that students can no longer rely on having their expenses paid for them. Formerly, students received a grant towards their living expenses. Now most can only get a loan (41) _____ has to be paid back. Since 1999 they have paid over £1,000 towards tuition fees and this amount will increase up to a maximum of £3,000. In the US students already have to pay for tuition and room and board.        Many get a financial aid package which may include grants, scholarships and loans. The fear of having large debts places (42) _____ pressure on students and many take part-time jobs during the term and work full-time in the vacations.

Tiếng Anh Tốt nghiệp THPT
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30 đề luyện thi Đại Học môn Tiếng Anh cực hay có lời giải (Đề số 23)

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questionsThe biologist's role in society as well as his moral and ethical responsibility in the discovery and development of new ideas has led to a reassessment of his social and scientific value systems. A scientist can no longer ignore the consequences of his discoveries; he is as concerned with the possible misuses of his findings as he is with the basic research in which he is involved. This emerging social and political role of the biologist and all other scientists requires a weighing of values that cannot be done with the accuracy or the objectivity of a laboratory balance. As a member of society, it is necessary for a biologist now to redefine his social obligations and his functions, particularly in the realm of making judgments about such ethical problems as man's control of his environment or his manipulation of genes to direct further evolutionary development.As a result of recent discoveries concerning hereditary mechanisms, genetic engineering, by which human traits are made to order, may soon be a reality. As desirable as it_may seem to be, such an accomplishment would entail many value judgments. Who would decide, for example, which traits should be selected for change? In cases of genetic deficiencies and disease, the desirability of the change is obvious, but the possibilities for social misuse are so numerous that they may far outweigh the benefits.Probably the greatest biological problem of the future, as it is of the present, will be to find ways to curb environmental pollution without interfering with man's constant effort to improve the quality of his life. Many scientists believe that underlying the spectre of pollution is the problem of surplus human population. A rise in population necessitates an increase in the operations of modern industry, the waste products of which increase the pollution of air, water, and soil. The question of how many people the resources of the Earth can support is one of critical importance.       Although the solutions to these and many other problems are yet to be found, they do indicate the need for biologists to work with social scientists and other members of society in order to determine the requirements necessary for maintaining a healthy and productive planet. For although many of man's present and future problems may seem to be essentially social, political, or economic in nature, they have biological ramifications that could affect the very existence of life itself.According to the passage, a modern scientist should be more concerned about __________.

Tiếng Anh Tốt nghiệp THPT
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20 BỘ ĐỀ THI THỬ THPT QUỐC GIA LẦN 1 NĂM HỌC 2018 - 2019 MÔN: TIẾNG ANH(ĐỀ 8)

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 38 to 42. Fill in the appropriate word in question 39        The popular image of student life is of young people with few responsibilities enjoying themselves and (38) _____ very little work. This is often not true. Many older people now study at college or university, sometimes (39) _____ a part-time basis while having a job and looking after a family. These students are often highly motivated and work very hard.        Younger students are often thought to be lazy and careless about money (40) _____ this situation is changing. In Britain reduced government support for higher education means that students can no longer rely on having their expenses paid for them. Formerly, students received a grant towards their living expenses. Now most can only get a loan (41) _____ has to be paid back. Since 1999 they have paid over £1,000 towards tuition fees and this amount will increase up to a maximum of £3,000. In the US students already have to pay for tuition and room and board.        Many get a financial aid package which may include grants, scholarships and loans. The fear of having large debts places (42) _____ pressure on students and many take part-time jobs during the term and work full-time in the vacations.

Tiếng Anh Tốt nghiệp THPT
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30 đề luyện thi Đại Học môn Tiếng Anh cực hay có lời giải (Đề số 23)

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questionsEthology is concerned with the study of adaptive, or survival, value of behavior and its Evolutionary history. Ethological theory began to be applied to research on children in the1960’s but has become even more influential today. The origins of ethology can be traced to the work of Darwin. Its modern foundations were laid by two European zoologists, Konrad Lorenz and Niko Tinbergen.Watching the behaviors diverse animal species in their natural habitats, Lorenz, and Tinbergen observed behavior patterns that promote survival. The most well-known of these is imprinting, the early following behavior of certain baby birds that ensures that the young will stay close to their mother and be fed and protected from danger. Imprinting takes place during an early, restricted time period of development. If the mother goose is not present during this time, but an object resembling her in important features is, young goslings may imprint on it instead . Observations of imprinting led to major concept that has been applied in child Development” the critical period . It refers to a limited times span during which the child is biologically prepared to acquire certain adaptive behaviors but needs the support of suitably stimulating environment. Many researchers have conducted studies to find out whether complex cognitive and social behaviors must be learned during restricted time periods. for example, if children are deprived of adequate food or physical and social stimulation during the early years of life, will their intelligence be permanently impaired? If language is not mastered during the preschool years, is the child’s capacity to acquire it reduced?          Inspired by observations of imprinting, in 1969 the British psychoanalyst John Bowlby applied ethological theory to the understanding of the relationship between an infant and its parents. He argued that attachment behaviors of babies, such as smiling, babbling, grasping, and crying, are built-in social signals that encourage the parents to approach, care for, and interact with the baby. By keeping a parent near, these behaviors help ensure that the baby will be fed, protected from danger, and provided with the stimulation and affection necessary for healthy growth. The development of attachment in human infants is a lengthy process involving changes in psychological structures that lead to a deep affectional tie between parent and baby.It can be inferred from the passage that ethological theory assumes that _____

Tiếng Anh Tốt nghiệp THPT
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Bài kiểm tra số 3

Cho 0,1 mol α-amino axit X tác dụng vừa đủ với 50 ml dung dịch HCl 2M. Trong một thí nghiệm khác, cho 26,7 gam X vào dung dịch HCl dư, cô cạn dung dịch thu được 37,65 gam muối khan. Vậy X là: 

Hóa học Lớp 12
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