题目内容

电路有3中工作状态，分别为（），（），（）。

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[音频]Have you ever heard others say “Cross your fingers” or “I’ll keep my fingers 1.for you”? The phrase “Cross your fingers” may leave some people scratching their 2.. This phrase is a wish for good 3.. It has something to do with the old belief in the strong 4.of the Christian cross. For those living in the old 5., they thought witches and ghosts 6.in the real world and they blamed illnesses and bad luck on evil 7.. The cross, they believed, could provide them protection and ward off the evil influence.Normally, making the 8. of the cross involves four steps--- touch the forehead, heart, left shoulder, then right shoulder with your right hand. However, one can make a cross shortcut by curling the middle finger of one hand. Although superstitions about the witches and evils slowly 9., the phrase “Cross one’s fingers” 10.. It is used for such a long time that it has 11.an idiom not only used by Christians but also those who do not 12.in God.

下列选项中，属于曲轴主轴承响的原因是（）

A. 机油压力太低，粘度太小或机油变质
B. 曲轴连杆轴承盖的固定螺栓松动或折断
C. 曲轴连杆轴承减磨合金烧毁或脱落
D. 曲轴内通连杆轴颈的油道堵塞

发动机异响主要有、、空气动力异响和电磁异响等。

发动机异响的主要影响因素是、、和润滑条件。