问题 选择题

下列关于安全用电的说法中,正确的是(  )

A.家里的保险丝熔断,一定是电路中出现了短路的故障

B.家里的保险丝熔断后,可用铜丝或铁丝来代替保险丝

C.当发现有人触电后,应该立即用手把触电人拉离电源

D.为防止锅体漏电造成触电事故,电饭锅采用三脚插头

答案

A、熔丝被烧断,有两种可能:用电器的总功率过大或发生短路;故A错.

B、保险丝采用电阻率大熔点低的铅锑合金制成,在电流过大时能自动切断电源.铜或铁的熔点高,在电流过大时不能自动切断电源,起不到保险的作用.故B错.

C、用手把触电人拉离电源,会造成被救者也触电,应立即切断电源或用绝缘体把导线挑开.故C错.

D、有金属外壳的家用电器,都要使用三脚插头,这是为了防止因漏电使外壳带电而造成触电事故.故D正确.

故选D.

选择题
阅读理解

阅读理解。

    Without plants, people could not live. We eat plants. We take in oxygen that plants make. And we need

plants for another reason: We need them because they are beautiful.

     Imagine a world with no plants. Imagine no flowers with their sweet smells, their beautiful colors and

their lovely shapes. Imagine, when the wind blows, we are not able to hear the leaves in the trees or watch

the branches swing from side to side. Everywhere people need beautiful plants. That is why we have parks

full of trees and flowers. That is why people always like houses with room for some grass and a garden.

     Do you talk to your plants? Do you give them love and take good care of them? Peter Tompkins and

Christopher Bird, writers of a book called THE SECRET LIFE OF PLANTS, tell of an experiment in which

two seeds were planted in different places. While the plants were growing, one plant was given love and

hopeful ideas. After six months, the beloved plant was bigger. Under the earth it had more and longer roots;

above the earth, it had a thicker stem and more leaves.

1. In the experiment, the two plants were _____. [ ]

A. talked to in two different ways

B. of different kinds

C. both given love and taken good care of

D. grown in the same place

2. At the end of six months _____. [ ]

A. the plants were of the same size

B. one plant had longer roots than the other

C. one plant had longer roots; the other plant had a thicker stem

D. one plant had a thicker stem; the other plant had more leaves

3. Tompkins and Bird believe that plants _____. [ ]

A. can talk to each other

B. can take care of each other

C. should be grown in different places

D. need love and care

4. The experiment tells us that _____. [ ]

A. without plants people could not live

B. we should talk to plants and give them love

C. we should grow as many plants as possible

D. plants need plenty of water, sunshine and fertilizer