There______ a coat and three shirts on the chair. [ ]
A. be
B. am
C. is
D. are
答案:C
计算泊松比σ
知:纵波速度Vp=3600m/s,横波速度Vs=2000m/s
求:σ=?(取三位小数)
下列哪个脏腑不会出现气虚()
A.心
B.肝
C.脾
D.肾