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Khái niệm

Chất béo có thành phần chính là 

Hóa học Lớp 12
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Đề minh hoạ kỳ thi THPTQG 2019 môn Hoá học có đáp án (Đề 15)

Hợp chất X là một saccarit, trong công nghiệp X còn được dùng để sản xuất ancol etylic và chế tạo thuốc súng không khói. Hợp chất X là

Hóa học Tốt nghiệp THPT
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30 đề thi thử đề thi thử THPTQG môn Tiếng Anh có lời giải chi tiết (Đề số 13)

Read the following passage and mark the letter A, B, C, or D to indicate the correct word or phrase that best fits each of the numbered blanks. Oxbridge is a word made from the names Oxford and Cambridge and is used to refer (46)_____ to the universities of Oxford and Cambridge together, especially when they are being distinguished from other universities. Oxford and Cambridge are the oldest universities in Britain. They are generally also thought to be the best universities to get a place at. An Oxbridge degree (47)_____ a good impression on many employers, and graduates of these universities may have an advantage when applying for jobs. The upper class has traditionally sent their children to Oxbridge, and many prime ministers and politicians went there. To many people, Oxford and Cambridge seem very remote places (48)_____ only the very privileged can go. The teaching system is different from that at most other universities. Students have tutorials, called supervisions at Cambridge, (49)_____ which they read their essays to their tutor. Terms are short and intense, and students are expected to prepare for them in the vacations. Final examinations at Oxford are called schools, and at Cambridge the trips. Undergraduates at Oxford and Cambridge study for a BA degree, but after a period of time graduates can (50)_____ their BA to an MA without doing any further study. Điền vào đáp án 47  

Tiếng Anh Tốt nghiệp THPT
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Tuyển tập đề thi thử Tiếng Anh cực hay có lời giải (Đề số 27)

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 28 to 35. Plastic bags are used by everybody. From a vegetable vendor to a designer store, everyone seems to use them. Even though they are one of the modern conveniences that we seem to be unable to do without, they are responsible for causing pollution, killing wildlife, and using up the precious resources of the Earth. But, most of us are blissfully unaware of the repercussions that are occurring and will take place in the future because of the plastic bags. Every once in a while, the government passes out an order banning store owners from providing plastic bags to customers for carrying their purchases, with little lasting effect. Plastic bags are very popular with both retailers as well as consumers because they are cheap, strong, lightweight, functional, as well as a hygienic means of carrying food as well as other goods. About a hundred billion plastic bags are used every year in the U.S. alone. And then, when one considers the huge economies and populations of India, China, Europe, and other parts of the world, the numbers can be staggering. The problem is further exacerbated by the developed countries shipping off their plastic waste to developing countries like India. Once they are used, most bags go into landfills. Each year, more and more bags are ending up littering the environment. Once they become litter, plastic bags find their way into our waterways, parks, beaches, and streets. And, if they are burned, they infuse the air with toxic fumes. About 100,000 animals, such as dolphins, turtles, whales, penguins are killed every year due to these bags. Many animals ingest plastic bags, mistaking them for food, and therefore, die. And worse, the ingested plastic bag remains intact even after the death and decomposition of the animal. Thus, it lies around in the landscape where another victim may ingest it. One of the worst environmental effects is that they are non-biodegradable. The decomposition takes about 400 years. No one will live so long to witness the decomposition of plastic! Thus, save the environment for the future generations as well as animals. Petroleum products are diminishing and getting more expensive by the day, since we have used this non-renewable resource increasingly. And to make plastic, about 60-100 million barrels of oil are needed every year around the world. Surely, this precious resource should not be wasted on producing plastic bags, should it? Petroleum is vital for our modern way of life. It is necessary for our energy requirements - for our factories, transportation, heating, lighting, and so on. Without viable alternative sources of energy yet on the horizon, if the supply of petroleum were to be turned off, it would lead to practically the entire world grinding to a halt. So, what can be done? A tote bag can make a good substitute for carrying groceries and the shopping. You can keep the bag with the cashier, and then put your purchases into it instead of the usual plastic bag. Recycling the bags you already have is another good idea. These can come into use for various purposes, like holding your garbage, instead of purchasing new ones. While governments may be working out ways to lessen the impact of plastic bags on the environment; however, each of us should shoulder some of the responsibility for this problem, which ultimately harms us. Plastics are not only non-biodegradable, but are one of the major pollutants of the sea. For a clean and green environment, try to use alternatives to plastic whenever and wherever possible. Cut down your use of plastic, and do your bit to save our planet. Question 32: The word "intact" in paragraph 3 is closest in meaning to ________.

Tiếng Anh Tốt nghiệp THPT
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500 bài tập lí thuyết Hóa Học nâng cao có lời giải (P7)

Cho các hợp chất sau: axetanđehit (1); metyl axetat (2);  axit fomic (3); etyl fomat(4);Glucozơ(5); axetilen(6). Số chất có thể tác dụng được với dung dịch AgNO3 trong NH3( trong điều kiện thích hợp)  là

Hóa học Tốt nghiệp THPT
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Tổng hợp đề luyện thi Đại Học môn Tiếng Anh có lời giải(Đề số 16)

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 28 to 34. The rules of etiquette of American restaurants depend upon a number of factors: the physical location of the restaurant, e.g. rural or urban, the type of restaurant, e.g. informal or formal, and certain standards that are more universal. In other words, some standards of etiquette vary significantly while other standards apply almost anywhere. Learning the proper etiquette in a particular type of restaurant in a particular area may sometimes require instruction, but more commonly, it simply requires sensitivity and experience. For example, while it is acceptable to read a magazine in a coffee shop, it is inappropriate to do the same in a more luxurious setting. And, if you are eating in a very simple setting, it may be fine to put your napkin into your shirt, but if you are in a sophisticated urban restaurant this behaviour would demonstrate a lack of manners. It is safe to say, however, that in virtually every restaurant it is unacceptable to indiscriminately throw your food on the floor. The conclusion we can most likely draw from the above is that while the types and locations of restaurants determine etiquette appropriate to them, some rules apply to all restaurants. What does the word “it” in the first paragraph refer to?

Tiếng Anh Tốt nghiệp THPT
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Đề minh hoạ kỳ thi THPTQG 2019 môn Hoá học có đáp án (Đề 15)

Chất nào sau đây không tác dụng với dung dịch NaOH?

Hóa học Tốt nghiệp THPT
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Bài 16: Luyện tập: Liên kết hóa học

Xác định số oxi hóa của Mn, Cr, Cl, P, N, S, C, Br: Trong ion: NO3-, SO42-, CO32-, Br-, NH4+.

Hóa học Lớp 10
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Tổng hợp đề luyện thi Đại Học môn Tiếng Anh có lời giải(Đề số 16)

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 28 to 34. The rules of etiquette of American restaurants depend upon a number of factors: the physical location of the restaurant, e.g. rural or urban, the type of restaurant, e.g. informal or formal, and certain standards that are more universal. In other words, some standards of etiquette vary significantly while other standards apply almost anywhere. Learning the proper etiquette in a particular type of restaurant in a particular area may sometimes require instruction, but more commonly, it simply requires sensitivity and experience. For example, while it is acceptable to read a magazine in a coffee shop, it is inappropriate to do the same in a more luxurious setting. And, if you are eating in a very simple setting, it may be fine to put your napkin into your shirt, but if you are in a sophisticated urban restaurant this behaviour would demonstrate a lack of manners. It is safe to say, however, that in virtually every restaurant it is unacceptable to indiscriminately throw your food on the floor. The conclusion we can most likely draw from the above is that while the types and locations of restaurants determine etiquette appropriate to them, some rules apply to all restaurants. According to the passage, which of the following is a universal rule of etiquette?

Tiếng Anh Tốt nghiệp THPT
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500 bài tập lí thuyết Hóa Học nâng cao có lời giải (P7)

Cho các chất sau : CO2, NO2, CO, CrO3, P2O5, Al2O3. Có bao nhiêu chất tác dụng được với dung dịch NaOH loãng ở nhiệt độ thường?

Hóa học Tốt nghiệp THPT
Xem chi tiết 512 lượt xem 6 năm trước
Khái niệm

Loại dầu, mỡ nào dưới đây không phải là lipit? 

Hóa học Lớp 12
Xem chi tiết 53 K lượt xem 6 năm trước
Tuyển tập đề thi thử Tiếng Anh cực hay có lời giải (Đề số 27)

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 28 to 35. Plastic bags are used by everybody. From a vegetable vendor to a designer store, everyone seems to use them. Even though they are one of the modern conveniences that we seem to be unable to do without, they are responsible for causing pollution, killing wildlife, and using up the precious resources of the Earth. But, most of us are blissfully unaware of the repercussions that are occurring and will take place in the future because of the plastic bags. Every once in a while, the government passes out an order banning store owners from providing plastic bags to customers for carrying their purchases, with little lasting effect. Plastic bags are very popular with both retailers as well as consumers because they are cheap, strong, lightweight, functional, as well as a hygienic means of carrying food as well as other goods. About a hundred billion plastic bags are used every year in the U.S. alone. And then, when one considers the huge economies and populations of India, China, Europe, and other parts of the world, the numbers can be staggering. The problem is further exacerbated by the developed countries shipping off their plastic waste to developing countries like India. Once they are used, most bags go into landfills. Each year, more and more bags are ending up littering the environment. Once they become litter, plastic bags find their way into our waterways, parks, beaches, and streets. And, if they are burned, they infuse the air with toxic fumes. About 100,000 animals, such as dolphins, turtles, whales, penguins are killed every year due to these bags. Many animals ingest plastic bags, mistaking them for food, and therefore, die. And worse, the ingested plastic bag remains intact even after the death and decomposition of the animal. Thus, it lies around in the landscape where another victim may ingest it. One of the worst environmental effects is that they are non-biodegradable. The decomposition takes about 400 years. No one will live so long to witness the decomposition of plastic! Thus, save the environment for the future generations as well as animals. Petroleum products are diminishing and getting more expensive by the day, since we have used this non-renewable resource increasingly. And to make plastic, about 60-100 million barrels of oil are needed every year around the world. Surely, this precious resource should not be wasted on producing plastic bags, should it? Petroleum is vital for our modern way of life. It is necessary for our energy requirements - for our factories, transportation, heating, lighting, and so on. Without viable alternative sources of energy yet on the horizon, if the supply of petroleum were to be turned off, it would lead to practically the entire world grinding to a halt. So, what can be done? A tote bag can make a good substitute for carrying groceries and the shopping. You can keep the bag with the cashier, and then put your purchases into it instead of the usual plastic bag. Recycling the bags you already have is another good idea. These can come into use for various purposes, like holding your garbage, instead of purchasing new ones. While governments may be working out ways to lessen the impact of plastic bags on the environment; however, each of us should shoulder some of the responsibility for this problem, which ultimately harms us. Plastics are not only non-biodegradable, but are one of the major pollutants of the sea. For a clean and green environment, try to use alternatives to plastic whenever and wherever possible. Cut down your use of plastic, and do your bit to save our planet. Question 31: The following are the negative effects of plastic bags on the environment, EXCEPT _________.

Tiếng Anh Tốt nghiệp THPT
Xem chi tiết 30.3 K lượt xem 6 năm trước
Ôn tập THPTGQ môn Hóa Học cực hay có đáp án (Đề số 16)

Phèn chua được dùng trong ngành thuộc da, công nghiệp giấy, chất cầm màu trong ngành nhuộm vải, chất làm trong nước, … Công thức của phèn chua là

Hóa học Tốt nghiệp THPT
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187 Bài trắc nghiệm Hàm số từ đề thi thử THPTQG 2019 cục hay có lời giải(P7)

Cho hàm số y=f(x) xác định trên ℝ\{1},  liên tục trên mỗi khoảng xác định và có bảng biến thiên như hình vẽ.Số giá trị nguyên của tham số m để phương trình f(x) = m có 3 nghiệm phân biệt là

Toán Lớp 12
Xem chi tiết 3.3 K lượt xem 6 năm trước
500 bài tập lí thuyết Hóa Học nâng cao có lời giải (P7)

Thực hiện các thí nghiệm sau : (1) Sục khí SO2 vào dung dịch KMnO4 .               (2) Sục khí Cl2 vào dung dịch H2S. (3) Sục hỗn hợp  khí thu được khi nhiệt phân Cu(NO3)2 vào nước.    (4) Cho Na2CO3 vào dung dịch AlCl3.                  (5) Cho HCl vào dung dịch Fe(NO3)2.                                                (6) Cho Fe2O3 vào dung dịch HI. Số thí nghiệm có phản ứng oxi hóa khử xảy ra là :

Hóa học Tốt nghiệp THPT
Xem chi tiết 357 lượt xem 6 năm trước
Khái niệm

Hãy cho biết hợp chất nào sau đây không có trong lipit? 

Hóa học Lớp 12
Xem chi tiết 25.1 K lượt xem 6 năm trước
Tổng hợp đề luyện thi Đại Học môn Tiếng Anh có lời giải(Đề số 16)

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 28 to 34. The rules of etiquette of American restaurants depend upon a number of factors: the physical location of the restaurant, e.g. rural or urban, the type of restaurant, e.g. informal or formal, and certain standards that are more universal. In other words, some standards of etiquette vary significantly while other standards apply almost anywhere. Learning the proper etiquette in a particular type of restaurant in a particular area may sometimes require instruction, but more commonly, it simply requires sensitivity and experience. For example, while it is acceptable to read a magazine in a coffee shop, it is inappropriate to do the same in a more luxurious setting. And, if you are eating in a very simple setting, it may be fine to put your napkin into your shirt, but if you are in a sophisticated urban restaurant this behaviour would demonstrate a lack of manners. It is safe to say, however, that in virtually every restaurant it is unacceptable to indiscriminately throw your food on the floor. The conclusion we can most likely draw from the above is that while the types and locations of restaurants determine etiquette appropriate to them, some rules apply to all restaurants. According to paragraph 1, which of the following statement is NOT true?

Tiếng Anh Tốt nghiệp THPT
Xem chi tiết 3.5 K lượt xem 6 năm trước
Tổng hợp đề luyện thi Đại Học môn Tiếng Anh có lời giải(Đề số 16)

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 28 to 34. The rules of etiquette of American restaurants depend upon a number of factors: the physical location of the restaurant, e.g. rural or urban, the type of restaurant, e.g. informal or formal, and certain standards that are more universal. In other words, some standards of etiquette vary significantly while other standards apply almost anywhere. Learning the proper etiquette in a particular type of restaurant in a particular area may sometimes require instruction, but more commonly, it simply requires sensitivity and experience. For example, while it is acceptable to read a magazine in a coffee shop, it is inappropriate to do the same in a more luxurious setting. And, if you are eating in a very simple setting, it may be fine to put your napkin into your shirt, but if you are in a sophisticated urban restaurant this behaviour would demonstrate a lack of manners. It is safe to say, however, that in virtually every restaurant it is unacceptable to indiscriminately throw your food on the floor. The conclusion we can most likely draw from the above is that while the types and locations of restaurants determine etiquette appropriate to them, some rules apply to all restaurants. What does the passage mainly discuss?

Tiếng Anh Tốt nghiệp THPT
Xem chi tiết 1.2 K lượt xem 6 năm trước
Tuyển tập đề thi thử Tiếng Anh cực hay có lời giải (Đề số 27)

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 28 to 35. Plastic bags are used by everybody. From a vegetable vendor to a designer store, everyone seems to use them. Even though they are one of the modern conveniences that we seem to be unable to do without, they are responsible for causing pollution, killing wildlife, and using up the precious resources of the Earth. But, most of us are blissfully unaware of the repercussions that are occurring and will take place in the future because of the plastic bags. Every once in a while, the government passes out an order banning store owners from providing plastic bags to customers for carrying their purchases, with little lasting effect. Plastic bags are very popular with both retailers as well as consumers because they are cheap, strong, lightweight, functional, as well as a hygienic means of carrying food as well as other goods. About a hundred billion plastic bags are used every year in the U.S. alone. And then, when one considers the huge economies and populations of India, China, Europe, and other parts of the world, the numbers can be staggering. The problem is further exacerbated by the developed countries shipping off their plastic waste to developing countries like India. Once they are used, most bags go into landfills. Each year, more and more bags are ending up littering the environment. Once they become litter, plastic bags find their way into our waterways, parks, beaches, and streets. And, if they are burned, they infuse the air with toxic fumes. About 100,000 animals, such as dolphins, turtles, whales, penguins are killed every year due to these bags. Many animals ingest plastic bags, mistaking them for food, and therefore, die. And worse, the ingested plastic bag remains intact even after the death and decomposition of the animal. Thus, it lies around in the landscape where another victim may ingest it. One of the worst environmental effects is that they are non-biodegradable. The decomposition takes about 400 years. No one will live so long to witness the decomposition of plastic! Thus, save the environment for the future generations as well as animals. Petroleum products are diminishing and getting more expensive by the day, since we have used this non-renewable resource increasingly. And to make plastic, about 60-100 million barrels of oil are needed every year around the world. Surely, this precious resource should not be wasted on producing plastic bags, should it? Petroleum is vital for our modern way of life. It is necessary for our energy requirements - for our factories, transportation, heating, lighting, and so on. Without viable alternative sources of energy yet on the horizon, if the supply of petroleum were to be turned off, it would lead to practically the entire world grinding to a halt. So, what can be done? A tote bag can make a good substitute for carrying groceries and the shopping. You can keep the bag with the cashier, and then put your purchases into it instead of the usual plastic bag. Recycling the bags you already have is another good idea. These can come into use for various purposes, like holding your garbage, instead of purchasing new ones. While governments may be working out ways to lessen the impact of plastic bags on the environment; however, each of us should shoulder some of the responsibility for this problem, which ultimately harms us. Plastics are not only non-biodegradable, but are one of the major pollutants of the sea. For a clean and green environment, try to use alternatives to plastic whenever and wherever possible. Cut down your use of plastic, and do your bit to save our planet. Question 30: According to the second paragraph, what is NOT true about the reality of plastic bags?

Tiếng Anh Tốt nghiệp THPT
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Bài 16: Luyện tập: Liên kết hóa học

Những nguyên tố nào sau đây có cùng cộng hóa trị trong các hợp chất khí với hiđro. P, S, F, Si, Cl, N, As, Te.

Hóa học Lớp 10
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Tổng hợp đề luyện thi Đại Học môn Tiếng Anh có lời giải(Đề số 16)

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 25 to 29. Fill in the appropriate word in question 29 How the Internet Is Changing Our Language There are words that we say today that 70 years ago weren’t even in (25) ____. If a person were to remark to a 1950s businessman, “Go and check this website out on the Internet and get back to me via Facebook,” the businessman would have no clue as to what had just been said. We know exactly what the words mean, though, so they (26) _____ perfect sense to us. The problem that people are encountering today is the same as the 1950s businessman would have encountered - he would have come (27)____a word that would mean nothing because he lived in a world where Internet technology is changing and progressing today at an even faster (28)_____, and this is creating changes in the way we communicate. Our words are different, and even our means of (29) _______ those words across are different as well. Forget about a 60-plus year difference; we speak much differently than we did even 10 or 20 years ago.

Tiếng Anh Tốt nghiệp THPT
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Tuyển tập đề thi thử Tiếng Anh cực hay có lời giải (Đề số 27)

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 28 to 35. Plastic bags are used by everybody. From a vegetable vendor to a designer store, everyone seems to use them. Even though they are one of the modern conveniences that we seem to be unable to do without, they are responsible for causing pollution, killing wildlife, and using up the precious resources of the Earth. But, most of us are blissfully unaware of the repercussions that are occurring and will take place in the future because of the plastic bags. Every once in a while, the government passes out an order banning store owners from providing plastic bags to customers for carrying their purchases, with little lasting effect. Plastic bags are very popular with both retailers as well as consumers because they are cheap, strong, lightweight, functional, as well as a hygienic means of carrying food as well as other goods. About a hundred billion plastic bags are used every year in the U.S. alone. And then, when one considers the huge economies and populations of India, China, Europe, and other parts of the world, the numbers can be staggering. The problem is further exacerbated by the developed countries shipping off their plastic waste to developing countries like India. Once they are used, most bags go into landfills. Each year, more and more bags are ending up littering the environment. Once they become litter, plastic bags find their way into our waterways, parks, beaches, and streets. And, if they are burned, they infuse the air with toxic fumes. About 100,000 animals, such as dolphins, turtles, whales, penguins are killed every year due to these bags. Many animals ingest plastic bags, mistaking them for food, and therefore, die. And worse, the ingested plastic bag remains intact even after the death and decomposition of the animal. Thus, it lies around in the landscape where another victim may ingest it. One of the worst environmental effects is that they are non-biodegradable. The decomposition takes about 400 years. No one will live so long to witness the decomposition of plastic! Thus, save the environment for the future generations as well as animals. Petroleum products are diminishing and getting more expensive by the day, since we have used this non-renewable resource increasingly. And to make plastic, about 60-100 million barrels of oil are needed every year around the world. Surely, this precious resource should not be wasted on producing plastic bags, should it? Petroleum is vital for our modern way of life. It is necessary for our energy requirements - for our factories, transportation, heating, lighting, and so on. Without viable alternative sources of energy yet on the horizon, if the supply of petroleum were to be turned off, it would lead to practically the entire world grinding to a halt. So, what can be done? A tote bag can make a good substitute for carrying groceries and the shopping. You can keep the bag with the cashier, and then put your purchases into it instead of the usual plastic bag. Recycling the bags you already have is another good idea. These can come into use for various purposes, like holding your garbage, instead of purchasing new ones. While governments may be working out ways to lessen the impact of plastic bags on the environment; however, each of us should shoulder some of the responsibility for this problem, which ultimately harms us. Plastics are not only non-biodegradable, but are one of the major pollutants of the sea. For a clean and green environment, try to use alternatives to plastic whenever and wherever possible. Cut down your use of plastic, and do your bit to save our planet. Question 29: What is the synonym of the word "repercussions" in the first paragraph?

Tiếng Anh Tốt nghiệp THPT
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Tổng hợp đề luyện thi Đại Học môn Tiếng Anh có lời giải(Đề số 16)

  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 25 to 29. Fill in the appropriate word in question 28 How the Internet Is Changing Our Language There are words that we say today that 70 years ago weren’t even in (25) ____. If a person were to remark to a 1950s businessman, “Go and check this website out on the Internet and get back to me via Facebook,” the businessman would have no clue as to what had just been said. We know exactly what the words mean, though, so they (26) _____ perfect sense to us. The problem that people are encountering today is the same as the 1950s businessman would have encountered - he would have come (27)____a word that would mean nothing because he lived in a world where Internet technology is changing and progressing today at an even faster (28)_____, and this is creating changes in the way we communicate. Our words are different, and even our means of (29) _______ those words across are different as well. Forget about a 60-plus year difference; we speak much differently than we did even 10 or 20 years ago.  

Tiếng Anh Tốt nghiệp THPT
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Bài 16: Luyện tập: Liên kết hóa học

Tinh thể nào dẫn điện được ở trạng thái rắn? Tinh thể nào dẫn điện được khi nóng chảy và khi hòa tan trong nước?

Hóa học Lớp 10
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Tuyển tập đề thi thử Tiếng Anh cực hay có lời giải (Đề số 27)

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 28 to 35. Plastic bags are used by everybody. From a vegetable vendor to a designer store, everyone seems to use them. Even though they are one of the modern conveniences that we seem to be unable to do without, they are responsible for causing pollution, killing wildlife, and using up the precious resources of the Earth. But, most of us are blissfully unaware of the repercussions that are occurring and will take place in the future because of the plastic bags. Every once in a while, the government passes out an order banning store owners from providing plastic bags to customers for carrying their purchases, with little lasting effect. Plastic bags are very popular with both retailers as well as consumers because they are cheap, strong, lightweight, functional, as well as a hygienic means of carrying food as well as other goods. About a hundred billion plastic bags are used every year in the U.S. alone. And then, when one considers the huge economies and populations of India, China, Europe, and other parts of the world, the numbers can be staggering. The problem is further exacerbated by the developed countries shipping off their plastic waste to developing countries like India. Once they are used, most bags go into landfills. Each year, more and more bags are ending up littering the environment. Once they become litter, plastic bags find their way into our waterways, parks, beaches, and streets. And, if they are burned, they infuse the air with toxic fumes. About 100,000 animals, such as dolphins, turtles, whales, penguins are killed every year due to these bags. Many animals ingest plastic bags, mistaking them for food, and therefore, die. And worse, the ingested plastic bag remains intact even after the death and decomposition of the animal. Thus, it lies around in the landscape where another victim may ingest it. One of the worst environmental effects is that they are non-biodegradable. The decomposition takes about 400 years. No one will live so long to witness the decomposition of plastic! Thus, save the environment for the future generations as well as animals. Petroleum products are diminishing and getting more expensive by the day, since we have used this non-renewable resource increasingly. And to make plastic, about 60-100 million barrels of oil are needed every year around the world. Surely, this precious resource should not be wasted on producing plastic bags, should it? Petroleum is vital for our modern way of life. It is necessary for our energy requirements - for our factories, transportation, heating, lighting, and so on. Without viable alternative sources of energy yet on the horizon, if the supply of petroleum were to be turned off, it would lead to practically the entire world grinding to a halt. So, what can be done? A tote bag can make a good substitute for carrying groceries and the shopping. You can keep the bag with the cashier, and then put your purchases into it instead of the usual plastic bag. Recycling the bags you already have is another good idea. These can come into use for various purposes, like holding your garbage, instead of purchasing new ones. While governments may be working out ways to lessen the impact of plastic bags on the environment; however, each of us should shoulder some of the responsibility for this problem, which ultimately harms us. Plastics are not only non-biodegradable, but are one of the major pollutants of the sea. For a clean and green environment, try to use alternatives to plastic whenever and wherever possible. Cut down your use of plastic, and do your bit to save our planet. Question 28: Which of the following could be the best tittle of the passage?

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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 25 to 29. Fill in the appropriate word in question 26 How the Internet Is Changing Our Language There are words that we say today that 70 years ago weren’t even in (25) ____. If a person were to remark to a 1950s businessman, “Go and check this website out on the Internet and get back to me via Facebook,” the businessman would have no clue as to what had just been said. We know exactly what the words mean, though, so they (26) _____ perfect sense to us. The problem that people are encountering today is the same as the 1950s businessman would have encountered - he would have come (27)____a word that would mean nothing because he lived in a world where Internet technology is changing and progressing today at an even faster (28)_____, and this is creating changes in the way we communicate. Our words are different, and even our means of (29) _______ those words across are different as well. Forget about a 60-plus year difference; we speak much differently than we did even 10 or 20 years ago.

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Sục khí X vào lượng dư dung dịch AgNO3 trong NH3, kết thúc phản ứng thu được kết tủa màu vàng nhạt. Khí X là

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