寒人经络，腰股腿足疼痛宜选
A．四逆散
B．四逆汤
C．当归四逆汤
D．通脉四逆汤
参考答案：C
相斥组
Scientists are convinced _______ the positive effect of laughter _______ physical and mental health.
[ ]
A. of; at
B. by; in
C. of; on
D. on; at
