大黄、芒硝、芦荟共有的功效是（）
A.泻下、止血
B.泻下、退黄
C.泻下、软坚
D.泻下、清热
E.泻下、活血
参考答案：D
我国四大主要工业基地均位于东部沿海地区，对其原因分析不正确的是（ ）
A．交通便利
B．海边风光好
C．人口稠密
D．工业基础好
—I didn't see her yesterday. —Of course, you ______, because she had gone to a trip.
A. can't B. may not haveC. can't have D. mustn't have
