There were so many cars held up by the heavy rain on the road that we had no        but to wait.

A．alternative

B．difference

C．relation

D．opposition

施工时进液管管卡或管固定件连接不牢固，会造成泵工作时（）。

A、停机

B、泵速变快

C、泵速变慢

D、泵体震动