大气过电压的持续时间一般为（）。A、几秒 B、几十毫秒 C、几_爱下问搜题

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问题单项选择题

大气过电压的持续时间一般为（）。

A、几秒

B、几十毫秒

C、几十微妙

D、几微秒

答案

参考答案：C

填空题

选词填空。
从方框里选择正确的单词，并用其正确的形式填空。

automatic, fit, stress, chemistry, survival, disappointed compre hend , shame , strong , pill

1. You need to be tough to ____ in the jungle.
2. The problem is beyond my _____.
3. To my _____, my father doesn't agree to buy me a new bike.
4. The poor boy was _____of his ragged clothes.
5. Phil is clearly ______to hold a senior position and he was fired soon.
6. Do you want anything from the ______?
7. She finds her new teaching job very ______.
8. Some doors have locks which _____lock the doors when we close them.
9. Occasionally she had to take sleeping ______.
10. The wind _____ last night.

单项选择题

下列哪项是标准状态（）。

A、1标准大气压20℃；

B、1标准大气压0℃；

C、1工程大气压273℃；

D、1工程大气压4℃。