静变流机将来自电瓶汇流条的直流电压转换成:A、单相115伏,400赫兹交流 B、三相1

题型:单项选择题

问题:

静变流机将来自电瓶汇流条的直流电压转换成:

A、单相115伏,400赫兹交流

B、三相115/200伏,400赫兹交流

考点:飞行员执照考试A320AV机型执照考试A320AV机型执照考试题库
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关于儿童疝,下列叙述哪项不正确()。

A.多为斜疝

B.90%发生嵌顿

C.婴幼儿疝有自行消失的可能

D.幼儿疝块由于组织菲薄,常能透光,易与睾丸鞘膜积液混淆

E.以上都不是

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You may keep the book for one more week _______no one else needs it.

A.provided that

B.so that

C.in order that

D.in case

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Because he wrote his name so that it could be read easily, John Hancock has a place in the dictionary.

John Hancock was a wealthy man who helped the patriots in the American Revolution. He was president of the Continental Congress. He was also governor of Massachusetts and one of the first men of sign the Declaration of Independence. Yet he is remembered best for his large signature.

The story is told that when Hancock sat down to sign the Declaration of Independence, he said that he would write his signature large enough for John Bull to read without his glasses. Hancock’s signature on the Declaration is four the three-quarter inches long—an inch longer than his usual signature.

Today John Hancock can be used to mean any person’s signature.

1. The passage is mainly about______________.

A. the American Revolution

B. John Hancock’s handwriting

C. how an American expression began

D. signing the Declaration of Independence

2. Hancock is remembered best because he________.

A. was governor of Massachusetts

B. helped the patriots in the Revolution

C. signed his name in large letters

D. was president of the Continental Congress

3. According to the dictionary, a John Hancock is a________.

A. governor                          B. man who sign petitions

C. strong patriot                     D. person’s signature

题型:单项选择题

双相触电在电弧焊接中不易发生。因此不太危险。()

题型:单项选择题

治导线由曲线段和直线段间隔组成,曲线段有复合圆弧曲线和余弦曲线。

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