— What's wrong with your iPad? The sound _____ is not clear.

— Yes. It has been broken for some time. [ ]

A. come out

B. coming out

C. to come out

D. came out

拉伸试验的试验速率对性能的测试有影响，总的趋势是速率增加（）升高，（）降低，速率降低，其影响趋势与上述相反，因此，拉伸试验时应严格执行标准中对速率的规定。

A.弹性性能

B.塑性性能

C.强度性能

D.断裂性能