试题与答案

PWM逆变电路的控制方式有()、()、()、()。

题型:填空题

题目:

PWM逆变电路的控制方式有()、()、()、()。

答案:

参考答案:同步调制;异步调制;分段同步调制;异步分段同步调制

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题型:填空题

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1. The teacher's talk made us so i_______ that we were all eager to have a try.

2. The teacher r_______ to in my last letter is going to work together with you next week.

3. As they m_______ each other, they are unlikely to reach an agreement on the matter.

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5. Much to my r_______, I am unable to accept your kind invitation.

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7. The magnificent tower must be saved, w______ the cost may be!

8. It rained; t______ the football match was put off until further notice.

9. A good sleeping bag is an essential part of every camper's e_______.

10. E______ yourself to sunlight for too much time will do harm to your skin.

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题型:单项选择题 共用题干题

男,45岁,近2个月来感胸闷、心悸、气促、乏力,逐渐出现少尿、下肢水肿。查体:颈静脉充盈,血压90/60mmHg,心浊音界向两侧扩大并随体位而改变,心音低钝,肝大,肝颈静脉回流征阳性。X线提示心脏阴影普遍性向两侧扩大,心脏搏动减弱。

如需与心力衰竭鉴别,最重要的心脏体征是有无()。

A.心率增快

B.心音低钝

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