根据波分光放大器的不同功能，放大器可分为（）。
A.后置放大器
B.前置放大器
C.线路放大器
D.功率放大器
参考答案：B, C, D
He ______ in Xinxiang for five years when I heard his news.[ ]
A. has lived
B. had lived
C. is living
D. has been lived
下列除哪项外.均是升浮类药一般具有的功效（）。
A.升阳发表
B.祛风散寒
C.潜阳熄风
D.涌吐
E.开窍
