进汽温度过高和过低会使汽轮机（）。
A、振动
B、叶片冲蚀
C、叶片断裂
D、零部件互相碰撞
参考答案：A, B, C, D
粘贴造口袋时，尽量避开（）、（）或皱褶处。
— Jenny _____ have kept her words. Why did she change her mind?
— I think she _____ give more explanations to us.
[ ]
A. should; has to
B. should; had better
C. should; should
D. ought to; need
