活塞环的端隙又称开口间隙，是活塞环自由状态下的开口处间隙。
查看答案
活塞销偏置的目的是防止活塞在换向时，撞击汽缸壁而产生“敲缸”
A. 对
B. 错
-The traffic jam is driving me mad! - _____ Such is often the case on Monday mornings.
A. Keep cool.
B. Well done.
C. No way.
D. Sounds good.
- Would you mind moving your bike? - _____ I’ll do it right away.
A. Of course.
B. Not in the least.
C. Never mind.
D. Why not?
A bicycle is often more _____ than a car in small towns.
A. dangerous
B. strict
C. convenient
D. vocational
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