TPO57阅读真题+题目+答案下载：Pests and Pesticides

TPO57阅读真题+题目+答案下载：Pests and Pesticides

Around 1870, a little fruit-eating insect arrived in San Jose, California, on some nursery stock shipped from Asia. The pest, which became known as the San Jose scale, quickly spread through the United States and Canada, killing orchard trees as it went. Farmers found that the best way to control the scale was to spray their orchards with a mixture of sulfur and lime. Within a few weeks of spraying a tree, the insect vanished completely.

1. The word "vanished" in the passage1 is closest in meaning to

A. recovered

B. disappeared

C. adapted

D. Retreated

Around the turn of the century, however, farmers began to notice that the sulfur-lime mixture was not working all that well. A handful of scales would survive a spraying and eventually rebound to their former numbers. In Clarkston Valley in Washington State, orchard growers became convinced that manufacturers were adulterating their pesticide. They built their own factory to guarantee a pure poison, which they drenched over their trees, yet the scale kept spreading uncontrollably. An entomologist named A. L Melander inspected the trees and found scales living happily under a thick crust of dried spray.

2. According to paragraph 2, how did farmers in Clarkston Valley explain the lack of success they were having with the use of the sulfur-lime mixture?

A. They suspected that surviving insects might have been a different variety of scale.

B. They believed that the mixture was not being applied to the trees properly.

C. They thought the mixture was being weakened by the manufacturers.

D. They assumed that the new scales were coming from nearby orchards.

Melander began to suspect that adulteration was not to blame. In 1912, he compared how effective the sprays were in different parts of Washington In Yakima and Sunnyside, he found that sulfur-lime could wipe out every last scale on a tree, while in Clarkston between 4 and 13 percent survived. On the other hand, the Clarkston scales were annihilated by a different pesticide made from fuel oil, just as the insects in other parts of Washington were. In other words, the scales of Clarkston had a peculiar resistance to sulfur-lime.

3. In paragraph 3, why does the author compare the effects of sulfur-lime pesticide in Yakima and Sunnyside with its effect in Clarkston?

A. To provide evidence that a new pesticide made from fuel oil was more effective than the sulfur-lime mixture

B. To explain why Melander thought that scales had become resistant to the pesticide

C. To indicate how Melander discovered that scale insects were killing trees throughout Washington

D. To illustrate the success of farmers who chose to manufacture their own pesticide

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