If the traffic light is red, you _____ cross the road. It's dangerous. [ ]

A. don't

B. needn't

C. mustn't

D. wouldn't

运行不当易引起（）产生裂纹。

A.调节级汽室

B.高压缸的上、下缸体结合面

C.中压缸的上、下缸体结合面

D.整个低压缸的内壁