They had camped once before, ____ they knew what to take.
A.because
B.now
C.so
D.since
答案:C
蜂窝织炎首选的物理因子为()
A.微波
B.紫外线
C.红外线
D.超声波
E.激光
如何评估团体心理咨询的效果?