Câu hỏi:
23/03/2020 412
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 30 to 37.
Humans have struggled against weeds since the beginnings of agriculture. Marring our gardens is one of the milder effects of weeds – any plants that thrive where they are unwanted. They clog waterways, destroy wildlife habitats, and impede farming. Their spread eliminates grazing areas and accounts for one-third of all crop loss. They compete for sunlight, nutrients, and water with useful plants.
The global need for weed control had been answered mainly by the chemical industry. Its herbicides are effective and sometimes necessary, but some pose serious problems, particularly if misused. Toxic compounds threaten animal and public health when they accumulate in food plants, groundwater, and drinking water. They also harm workers who apply them.
In recent years, the chemical industry has introduced several herbicides that are more ecologically sound. Yet new chemicals alone cannot solve the world’s weed problems. Hence, scientists are exploring the innate weed-killing powers of living organisms, primarily insects and microorganisms.
The biological agents now in use are environmentally benign and are harmless to humans. They can be chosen for their ability to attack selected targets and leave crops and other plants untouched. In contrast, some of the most effective chemicals kill virtually all the plants they come in contact with, sparing only those that are naturally resistant or have been genetically modified for resistance. Furthermore, a number of biological agents can be administered only once, after which no added applications are needed. Chemicals typically must be used several times per growing season.
With what topic does this passage primarily deal?
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Trả lời:
Đáp án D
Chủ đề nào đoạn văn này chủ yếu giải quyết?
A. Sự nguy hiểm của hóa chất độc hại.
B. Đề xuất cấm sử dụng tất cả các chất diệt cỏ.
C. Tầm quan trọng của ngành công nghiệp hoá chất.
D. Ưu điểm của tác nhân sinh học hơn những hóa chất.
CÂU HỎI HOT CÙNG CHỦ ĐỀ
Câu 1:
Mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions.
He wanted to know _________shopping during the previous morning.
Câu 2:
Mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions.
The Red Cross is an international organization that helps people who are suffering from the results of war, diseases or _______.
Câu 3:
Mark the letter A, B, C or D on your answer sheet to indicate the word(s) CLOSET in meaning to the underlined word(s) in each of the following questions.
Roget's Thesaurus, a collection of English words and phrases, was originally arranged by the ideas they express rather than by alphabetical order.
Câu 4:
Mark the letter A, B, C or D on your answer sheet to indicate the word(s) OPPOSITE in meaning to the underlined word(s) in each of the following questions.
Each time you turn it on, with appropriate hardware and software, it is capable of doing almost anything you ask.
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.
He advised them _________ in the class
Câu 6:
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.
We had planned to walk right round the lake, but the heavy rain made this impossible.
Câu 7:
Mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions.
Williams is working _______ an export company. He intends to apply _______ another job because he is not satisfied _______ the salary.
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