Câu hỏi:
13/07/2024 165Read 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
For which of the following reasons can natural pollutants play an important role in controlling air pollution?
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Trả lời:
Giải bởi Vietjack
Đáp án A
Đề: Vì lý do nào sau đây mà các chất gây ô nhiễm tự nhiên đóng vai trò quan trọng trong việc kiểm soát sự ô nhiễm không khí?
A. Chúng hoạt động với chức năng là một phần của quá trình thanh lọc.
B. Chúng xuất hiện với số lượng lớn hơn nhiều so với các chất gây ô nhiễm khác.
C. Chúng ít có hại tới các sinh vật sống hơn so với các chất gây ô nhiễm khác.
D. Chúng đã luôn tồn tại từ khi trái đất hình thành.
Đoạn 2: “Many of the more important air pollutants, such as… 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…”
Dịch: Nhiều chất gây ô nhiễm không khí quan trọng/nghiêm trọng hơn, như… được tìm thấy trong tự nhiên. Khi trái đất hình thành/phát triển, chúng trở thành các thành phần trong các chu kỳ sinh hoá. Chúng có tác dụng như là một cách thanh lọc không khí…
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
38,672
Câu 2:
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
11,434
Câu 3:
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
11,377
Câu 4:
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
11,348
Câu 5:
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
11,189
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
Xem đáp án »
14/04/2020
11,031
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.
Xem đáp án »
14/04/2020
8,598
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