单级振荡式发射机的脉冲调制器向微波振荡器提供（），从而使大功_爱下问搜题

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问题单项选择题

单级振荡式发射机的脉冲调制器向微波振荡器提供（），从而使大功率微波振荡器产生周期性的脉冲射频信号。

A.连续的高频正弦波电压

B.周期性的高频正弦波电压

C.周期性的脉冲高压

D.周期性的交流电压

答案

参考答案：C

填空题

从方框中选择正确的词组完成句子（每词只用一次，注意将动词改成正确形式）。

a lot of, twice a day, happen to, too much, take a look at, take off, have a haircut, lift heavy things, lose weight, read in the sun

1. Bob has a backache. Now the doctor              his back.
2. Judy looks sad (难过). What               her just now?
3. You're a little near-sighted. You'd better not              .
4. When you have a fever, you should drink              water.
5. You must lie down and don't move your leg              .
6. We should clean our classroom              .
7. My father's left arm hurts badly and he can't              .
8. You get so fat and you should              .
9. It's so hot today. You'd better              your jacket.
10. Matthew's hair is too long. He should              .

填空题

Token Bus局域网中的令牌是一种特殊的控制帧，用来控制结点对总线的【6】。