与“看电影”相同组合类型的短语是（）。
A.看一本
B.看一回
C.看一次
D.看一遍
参考答案：A
怎样确定泵的级数？
— Why didn’t you try your best to get on the subway?
— I tried to, but it started moving ______ I could get on it.
A．before
B．after
C．since
D．if
