Câu hỏi:
14/04/2020 307Read 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 questions from 22 to 28.
An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled - a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of the health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.
Many of the more important air pollutants, such as sulfur oxides, carbon monoxide, and nitrogen oxides, are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature's output of these compounds dwarfs that resulting from human activities.
However, human production usually occurs in a localized area, such as a city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an increased concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact, the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0.08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however, has a natural level of 0.1 ppm and is not usually a pollutant until its level reaches about 15 ppm
It can be inferred from the first paragraph that ________.
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Trả lời:
Giải bởi Vietjack
Đáp án C
Đề: Có thể được suy luận ra từ đoạn văn đầu tiên rằng…
A. hơi nước là một chất gây ô nhiễm không khí ở các khu dân cư
B. hầu hết các chất gây ô nhiễm không khí ngày nay có thể được nhìn thấy hoặc ngửi thấy
C. định nghĩa về ô nhiễm không khí sẽ tiếp tục thay đổi
Dựa vào câu 2: “Air pollution requires a very flexible definition that permits continuous change.”
Dịch: Sự ô nhiễm không khí đòi hỏi một sự định nghĩa linh hoạt mà cho phép có sự thay đổi không ngừng/liên tục
Nhà sách VIETJACK:
CÂU HỎI HOT CÙNG CHỦ ĐỀ
Câu 1:
Mark the letter A, B, C, or D on your answer sheet to show the underlined part that needs correction
A paragraph is a portion of a text consists of one or more sentences related to the same idea.
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14/04/2020
38,288
Câu 2:
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.
Tom has the ability to be a professional musician, but he’s too lazy to practice.
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14/04/2020
11,300
Câu 3:
Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that best combines each pair of sentences in the following questions.
I had never met Rose before. However, I recognized her from a picture
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14/04/2020
11,270
Câu 4:
Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions
Tim finds mending old clothes incredibly _______, that's why he always asks his mother to do it for him.
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14/04/2020
11,111
Câu 5:
Mark the letter A, B, C, or D on your answer sheet to indicate the most suitable response to complete each of the following exchanges
– “What do you usually do at weekend?” – “_______.”
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14/04/2020
11,062
Câu 6:
Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that best combines each pair of sentences in the following questions.
The human brain is 8 times the size of a monkey’s. It weighs about 1,400 grams
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14/04/2020
10,979
Câu 7:
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.
The teacher couldn’t stand my brother’s manner.
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14/04/2020
8,565
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