题干

静电现象在自然界中普遍存在,我国早在西汉末年已有对静电现象的记载,《春秋纬•考异邮》中有“玳瑁吸”之说,但下列不属于静电现象的是(  )

A:梳过头发的塑料梳子吸起纸屑

B:带电小球移至不带电金属附近,两者相互吸引

C:小线图接近通电线圈过程中,小线圈中产生电流

D:从干燥的地毯上走过,手碰到金属把手时有被电击的感觉

上一题 下一题 0.0难度 选择题 更新时间:2019-12-27 11:44:37

答案(点此获取答案解析)

C

同类题4

根据短文内容,从短文后的选项中选出能填入空白处的最佳选项,并在答题卡上将该项涂黑。选项中有两项为多余选项。

      Sleep is something we all do. But some people need to sleep more than others. Babies sleep most of the time. Children in school sleep about ten to twelve hours a night. Most adults sleep only seven or eight hours.____All parts of our bodies have to rest after they work.. Our arms need a rest after we lift heavy thing, When we run fast, our legs work hard. They get tired. We have to rest them. Our brains workhard, too.____ We can sit quite still and rest our arms andlegs. But our brains aren't resting. They go right on thinking as long as weare awake.

      Our brains slow down a bit when we sleep and dream.____ Instead of thinking wide-awake thoughts, our brains make up dreams. Some dreams are very pleasing. Some are not. Most of thetime we forget them when we wake up.

      Scientists have tried to find out what would happen if people were not allowed to sleep. They asked some people not to go to bed. The people stayed up all night and all the next day. They stayed up the next night too,and the day after. They played games, but they made mistakes. They forgot things.____ The people grew rude and mean. They became angry with their friends. Finally they were too tired to stand up. When they sat down, they fell asleep.

      Scientists have found that if people are not allowed to sleep and to dream, they act in an unusual way.____But we do know that we need it to stay well. So tonight have a goodsleep. Lie down under the covers. Shut your eyes. Let your thoughts wander.Soon you’ll stop thinking. You'll be asleep.

A. It was hard for their tired brains to work.

B. When we are awake, they help us pay attention to the worldaround us

C. But babies, children, and adults----all of us need to haveour sleep

D. Good sleep helps to improve one's memory

E. No one knows why sleep is so good for us

F. But even as we sleep our brains are doing some work

G. Of course you will have a good sleep