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Câu hỏi: 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.
A useful definition of an air pollutant is a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals vegetations, 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 concentrations of these pollutants were altered by various chemical reactions, they became components in biogeochemical cycle. These serve as an ai purifiation 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 this localized regions human output may be dominant and may temporarily overload the natural purifiation scheme of the cycle The result is an increased concentration of 20% 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.
ppm and is not usually a pollutant until its level reaches about 15 ppm.
A. water vapor is an air pollutant in localized areas.
B. a substance becomes an air pollutant only in cities.
C. most air pollutants today can be seen or smelled.
D. the definition of air pollution will continue to change.
A useful definition of an air pollutant is a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals vegetations, 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 concentrations of these pollutants were altered by various chemical reactions, they became components in biogeochemical cycle. These serve as an ai purifiation 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 this localized regions human output may be dominant and may temporarily overload the natural purifiation scheme of the cycle The result is an increased concentration of 20% 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.
ppm and is not usually a pollutant until its level reaches about 15 ppm.
(Adapted from http://www.livescience.com)
It can be inferred from the first paragraph thatA. water vapor is an air pollutant in localized areas.
B. a substance becomes an air pollutant only in cities.
C. most air pollutants today can be seen or smelled.
D. the definition of air pollution will continue to change.
Giải thích:
Có thể suy ra từ đoạn thứ nhất rằng ____.
A. hơi nước là một chất gây ô nhiễm không khí ở các khu vực địa phương hóa.
B. chỉ ở thành phố thì một chất mới trở thành chất gây ô nhiễm không khí
C. đa số các chất gây ô nhiễm không khí có thể được nhìn thấy hoặc ngửi thấy.
D. định nghĩa về ô nhiễm không khí sẽ tiếp tục thay đổi.
Thông tin:
+ In the future, even water vapor might be considered an air pollutant under certain conditions. (Trong tương lai, ngay cả hơi nước cũng được xem là một chất gây ô nhiễm không khí trong điều kiện nhất định.)
→ A sai
+ B: không đề cập → loại B
+ 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. (Khi luật ô nhiễm không khí đầu tiên được ban hành tại Anh vào thế kỷ 14, các chất gây ô nhiễm không khí chỉ được giới hạn trong các hợp chất có thể nhìn thấy hoặc ngửi thấy từ xa - khác hẳn với danh sách mở rộng các chất gây hại được biết đến ngày nay.)
→ C sai
+ Air pollution requires a very flexible definition that permits continuous change. (Sự ô nhiễm không khí đòi hỏi một định nghĩa linh hoạt cho phép những thay đổi liên tục.)
→ D đúng/.
Có thể suy ra từ đoạn thứ nhất rằng ____.
A. hơi nước là một chất gây ô nhiễm không khí ở các khu vực địa phương hóa.
B. chỉ ở thành phố thì một chất mới trở thành chất gây ô nhiễm không khí
C. đa số các chất gây ô nhiễm không khí có thể được nhìn thấy hoặc ngửi thấy.
D. định nghĩa về ô nhiễm không khí sẽ tiếp tục thay đổi.
Thông tin:
+ In the future, even water vapor might be considered an air pollutant under certain conditions. (Trong tương lai, ngay cả hơi nước cũng được xem là một chất gây ô nhiễm không khí trong điều kiện nhất định.)
→ A sai
+ B: không đề cập → loại B
+ 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. (Khi luật ô nhiễm không khí đầu tiên được ban hành tại Anh vào thế kỷ 14, các chất gây ô nhiễm không khí chỉ được giới hạn trong các hợp chất có thể nhìn thấy hoặc ngửi thấy từ xa - khác hẳn với danh sách mở rộng các chất gây hại được biết đến ngày nay.)
→ C sai
+ Air pollution requires a very flexible definition that permits continuous change. (Sự ô nhiễm không khí đòi hỏi một định nghĩa linh hoạt cho phép những thay đổi liên tục.)
→ D đúng/.
Đáp án D.