Dear Xiaohua,

I’m very glad to receive your letter. From your letter I know you have shown 小题1:______ great interest in inventing new things. That’s great. As for how to be an inventor, there is no quick answer to 小题2:______.

Coming from different cultures and having different backgrounds, inventors don’t seem to have much 小题3:______ common. But creative thinking, 小题4:_______ is greatly valued, is perhaps the basic skill an inventor should have. In order to explore new possibilities, you will have to learn to break小题5:______ from old thought patterns. When you get stuck, try to look at the problem in 小题6:____ many ways as possible. Each new way may improve your understanding.

More importantly, always keep it in mind 小题7:______ success is no accident. It is the result of a long process of trial and error. Above 小题8:_____, the main task for you is to study hard and try to learn more knowledge. This, of course, will lay a solid foundation.

Hope your future invention will make a difference.

Good luck!

Yours,

Wang Li

采用裸铜线作为固定电气设备接地线时，导线截面应不小于（）。

A.4mm²

B.2.5mm²

C.1.5mm²

D.1.0mm²