往复泵的流量取决于（）。
A.活塞面积
B.冲程
C.冲数
D.出口阀开度
参考答案：A, B, C
— What do you think we can do for our aged parents?
— You _____ do anything except to be with them and be yourself.
A. don't have to
B. oughtn't to
C. mustn't
D. can't
痰热互结，症见胸脘痞闷，咳痰黄稠，苔黄腻，脉滑数者，治宜选用( )
A．温胆汤B．滚痰丸C．小陷胸汤D．大陷胸汤E．清气化痰丸
