下合穴中可治疗肠痈、痢疾的是（）。
A.足三里
B.上巨虚
C.下巨虚
D.委中
E.阳陵泉
参考答案：B
两个质数的和是20，积是91，它们是______和______．
--- Where is your teacher?
--- I don't know, I think she is ____________ classroom. [ ]
A. at
B. in
C. in the
