John _______ at his uncle’s for 3 days and he is now at home.

A．stayed

B．has stayed

C．had stayed

D．was staying

配伍中寓有“通因通用”之意的方剂是（）

A.白头翁汤

B.清胃散

C.苇茎汤

D.芍药汤

E.凉膈散