Câu hỏi:
19/04/2023 151
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
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 changes. 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 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 more important air pollutants, such as sulfur oxides, carbon monoxides 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 region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an 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.
The word "detectable " is closest in meaning to
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
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 changes. 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 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 more important air pollutants, such as sulfur oxides, carbon monoxides 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 region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an 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.
The word "detectable " is closest in meaning to
Đáp án chính xác
Câu hỏi trong đề:
Trắc nghiệm tổng hợp Tiếng anh có đáp án 2023 !!
Hot: Hot: 500+ Đề thi thử tốt nghiệp THPT Quốc gia Toán, Văn, Anh, Sử, Địa...., ĐGNL các trường ĐH Quốc Gia Hà Nội, Tp. Hồ Chi Minh file word có đáp án (form 2025).
Quảng cáo
Trả lời:
Giải bởi Vietjack
Thông tin: “A useful definition of an air pollutant”, “Many of the more important air pollutants”, “The actual concentration need not be large for a substance to be a pollutant”
Chọn D
Nhà sách VIETJACK:
Sổ tay dẫn chứng nghị luận xã hội - VietJack (Sách 2025 theo chương trình mới)
Đã bán 1k
₫ 36.000
₫ 18.000
Sách - Sổ tay kiến thức trọng tâm Ngữ Văn 12 VietJack - Sách 2025 theo chương trình mới cho 2k7
Đã bán 2,3k
₫ 36.000
₫ 18.000
Combo - Sổ tay Lý thuyết trọng tâm lớp 12 các môn Toán, Lí, Hóa, Văn, Sử, Địa, KTPL
Đã bán 1,5k
₫ 70.000
₫ 36.000
Sách Combo - Tuyển tập 30 đề thi đánh giá năng lực Đại học Quốc gia TP Hồ Chí Minh (2 cuốn) - 2024 cho 2k7 VietJack
Đã bán 1,4k
₫ 280.000
₫ 150.000
Bình luận
CÂU HỎI HOT CÙNG CHỦ ĐỀ
Câu 1:
In case you're suffered from the injury, you _____ see the doctor today.
In case you're suffered from the injury, you _____ see the doctor today.
Xem đáp án »
10/01/2025
24,034
Câu 4:
Henry _______ into the restaurant when the writer was having dinner.
Henry _______ into the restaurant when the writer was having dinner.
Xem đáp án »
19/04/2023
14,411
Câu 5:
We’ve divided the group report into three parts and you're ___ for the conclusion one
We’ve divided the group report into three parts and you're ___ for the conclusion one
Xem đáp án »
19/04/2023
12,280
Câu 6:
The child was .................... by a lorry on the safety crossing in the main street.
The child was .................... by a lorry on the safety crossing in the main street.
Xem đáp án »
12/01/2025
9,918
Câu 7:
Talking to professional counsellors who are trained to help people to process feelings, can be most _____.
Talking to professional counsellors who are trained to help people to process feelings, can be most _____.
Xem đáp án »
19/04/2023
9,170
🔥 Đề thi HOT:
-
Bộ câu hỏi: [TEST] Từ loại (Buổi 1) (Có đáp án)
-
Trắc nghiệm Tiếng anh 12 Tìm từ được gạch chân phát âm khác - Mức độ nhận biết có đáp án
-
Bài tập chức năng giao tiếp (Có đáp án)
-
Bộ câu hỏi: Các dạng thức của động từ (to v - v-ing) (Có đáp án)
-
500 bài Đọc điền ôn thi Tiếng anh lớp 12 có đáp án (Đề 1)
-
Bộ 5 đề thi giữa học kì 2 Tiếng Anh lớp 12 Global Success có đáp án (Đề 1)
-
Bộ câu hỏi: Thì và sự phối thì (Phần 2) (Có đáp án)
-
Đề kiểm tra học kì 2 Tiếng anh 12 năm 2023 có đáp án (Đề 28)
Hãy Đăng nhập hoặc Tạo tài khoản để gửi bình luận
-
-
Bình luận