Which of your hands do you use most ? Very few of us use both of our hands well. Most of us are right-handed. Only about five people out of a hundred are left-handed. New-born babies can take things with either of their hands, but in about two years they like to use their right hands. Scientists don't know why this happens. They have studied it. They think our animal ancestors(祖先) are right-handed. This may not be true. Monkeys are our closest relations in the animal world. Scientists have found that monkeys like to use one of their hands more than the other—but it can be either hand. There are as many right-handed ones. Next time you visit the zoo, watch the monkeys carefully. You'll see that some of them will swing(摆动)from their right hands and others will use their left hands. But most human beings(人类) use their right hands better and this makes life difficult for the left-handed ones. We live in a right-handed world.

补全对话(方框中有两项是多余的)

A：Hi，Betty．What are you going to do?

B：Hi，Lingling!____  

A：Oh，I have just come from there．

B：____ 

A：Yes．There will be an English speaking competition next Friday．

B:____

A: Life in the Future．

B: That's a good topic．  ____ 

A: Yes, I'd like to．I think I can practise my spoken English．What about you?

B：Oh，you know，I am shy．I am afraid I can't speak in public．

A：____ If you keep on practising，you will be successful．

B：I will think about it．Thank you very much

迭到一起的总面积是多少 ？

1902年美国已有发电厂3621座，总装机容量121．2万千瓦；1907年德国已有三分之一的企业使用电动机。这预示人类进入到（    ）