对感觉和运动神经均能起抑制作用的电针波形是（）
A.密波
B.疏波
C.疏密波
D.断续波
E.锯齿波
参考答案：A
Nobody knows _____. [ ]
A. who lives in that house
B. what did he say
C. where does she want to go
We thought of selling this old furniture, but we've decided to it. It might be valuable. [ ]
A. hold on to
B. keep up with
C. turn to
D. look after
