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.
Which of the following statements about the use of chemical agents as herbicides would the author most likely agree?
A. It has become more dangerous recently.
B. It is occasionally required.
C. It is safe but inefficient.
D. It should be increased.
Đáp án B
Câu nào trong những câu sau đây về việc sử dụng các tác nhân hóa học như chất diệt cỏ tác giả có thể đồng ý?
A. Gần đây đã trở nên nguy hiểm hơn.
B. Nó thỉnh thoảng cần thiết.
C. Nó an toàn nhưng không hiệu quả.
D. Nó nên được tăng lên.
Thông tin: The global need for weed control had been answered mainly by the chemical industry. Its herbicides are effective and sometimes necessary (Nhu cầu kiểm soát cỏ dại toàn cầu đã được hồi đáp chủ yếu bởi ngành công nghiệp hoá chất. Thuốc diệt cỏ có hiệu quả và đôi khi cần thiết)