化合物半导体砷化镓常用的施主杂质是（）。
A.锡
B.硼
C.磷
D.锰
参考答案：A
The coin, which ______ the 1920, ______.
A．dated from; belongs to mine
B．dates from; belongs to me
C．dates back to; made of gold
D．was dated from; was stolen
急性肺水肿抢救时不宜选用（）
A.依那普利
B.吗啡
C.呋塞米
D.硝普钠
E.氨茶碱
