往复泵的检修中液缸内表面应（）。
A.光滑、无裂纹
B.无砂眼
C.无沟槽
D.重新刷镀
参考答案：A, B, C
Mr. Smith as well as his wife and daughter, _____ to their school twice.
A．have gone
B．has gone
C．have been
D．has been
能攻下热积的药物是
A．芒硝
B．牵牛子
C．巴豆
D．大黄
