The World Health Organization now supports the use of DDT in homes to control malaria. The agency supported indoor spraying with DDT and other insect poisons until the early 1980s. It stopped as health and environmental concerns about DDT increased.

　　But last Friday, an assistant director-general of the United Nations agency announced a policy change. Doctor Asamoa-Baah said indoor spraying is useful to quickly reduce the number of infections caused by malaria-carrying mosquitoes. He also stressed that DDT presents on health risk when used correctly.

　　The WHO says it supports indoor spraying in areas with high malaria rates, including throughout Africa. But its malaria program director, Arata Kochi, says DDT should be used only inside houses and huts, not outside and not for agriculture use.

　　In the 1940s DDT was found to be an excellent way to control insects. It cost little to produce and was not found to harm humans. So it was widely used for people and crops.

　　In the 1960s, environmentalist Rachel Carson and her book “Silent Spring” led to a movement to ban it. The United States did just that a decade later.

　　Yet the rise of malaria has led some environmental groups to change their thinking. The group Environmental Defense, which led the anti-DDT movement, now supports indoor use to control malaria.

　　But many critics of DDT worry it will not be used with great care. University of Illinois scientist May Berenbaum argues that DDT is not as effective as people might think. Writing in the Washington Post, she noted that some African mosquitoes developed resistance to it. She says DDT should be only one tool among many for insect control.

　　The WHO supports other interventions as well. But it says India sharply cut malaria rates in the past with indoor use of DDT. And ten countries in southern Africa are currently using it for malaria control.

　　1. When did American stop using DDT?

　　A. In the 1940s.

　　B. In the 1960s.

　　C. In the 1970s.

　　D. In the 1980s.

　　2. What do you think the book “Silent Spring” is about?

　　A. About the harm DDT does to humans.

　　B. About DDT in the water from a spring.

　　C. About DDT in the water used for controlling insects.

　　D. About DDT used for people and crops.

　　3. Which of the following is not true?

　　A. DDT may be harmful when used incorrectly.

　　B. Environmental Defense admits DDT can control malaria.

　　C. DDT may be harmful to the environment and crops.

　　D. All scientists agree to spray DDT indoors now.

　　4. What does the word “It” in the last sentence of Para. 1 refer to?

　　A. “The use of DDT” B. “Mosquito”

　　C. “The WHO” D. “Malaria”

　　5. What can you infer from the passage?

　　A. People’s knowledge of a thing is always developing.

　　B. DDT is very useful.

　　C. There are many tools to control malaria.

　　D. India has never stopped using DDT.

　　解读：本文为说明文，主要介绍联合国世界卫生组织决定重新启用被人们废弃多年的农药DDT。世界卫生组织认为，尽管一些科学家反对使用DDT，但是DDT对消灭苍蝇，减少疟疾的传播很有好处。

　　答案及解析

　　1. C 推断题。根据第五段中的“In the 1960s”及“a decade later”可知，答案选C。

　　2. A 推断题。根据文章内容可知，由于此书的出现，人们改变了对DDT的看法，接着停止了对DDT的使用因此我们断定，此书是谈论DDT对人们的危害的。

　　3. D 判断题。根据文章倒数第二段第一句“But many critics of DDT worry in will not be used with great care”及全段内容可知，有些科学家仍然反对使用DDT，由此可见并不是所有的科学家都同意，答案选D。

　　4. A 理解题。根据“It”所在句前面的内容可知，这里的“It”指的是对DDT的使用，答案选A。

　　5. A 推断题。根据本文内容，人们对DDT从禁用到重新启用，说明人们对事物的认识是不断发展变化的。答案选A。