题目内容

三相桥式PWM逆变电路的结构，是采用双极性调制方法。

A. 对
B. 错

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Section DListen to the following passage and fill the missing words in the blanks.There is more in 20 than just learning facts. We go to school, above all, to learn how to learn, 21, when we have left school, we can continue to learn. A man who really knows how to learn will always be 22, because whenever he has to do something new which he has never had to do before, he will rapidly teach himself how to do it in the best way. The uneducated person, on the other hand, is 23 unable to do something new, or does it 24. The purpose of schools, therefore, is not just to teach languages, arithmetic(算术), geography, etc., but teach pupils the way to learn.

Section AListen to the questions and choose the best answer to each of them.

A. It's the second.
B. Yesterday.
C. 4:00 p.m.
D. It's Saturday.

2

About 2 kilometres.
B. You can take the No.1 bus.
C. In 20 minutes.
D. It's not far.

3

A. Yes, it is.
B. It's too late.
C. Take it easy.
D. It doesn't matter.