开采多层地下水时，若各含水层水质差异大，应当( )。
A．混合开采
B．统一开采
C．保守开采
D．分层开采
参考答案：D
What I had to do during the rest of the days _____ death. [ ]
A. to wait for
B. to wait
C. was to wait
D. was to wait for
下列（）景点和曹雪芹以及他的红楼梦有关。
A．上海的大观园
B．北京香山地区曹雪芹纪念馆
C．北京大观园
D．上海曹雪芹纪念馆
E．北海公园
