He helps his friends ___________ their English.[ ]
A. on
B. in
C. with
D. at
答案:C
常合并出现积滞的病证有()。
A.感冒
B.哮喘
C.疳证
D.泄泻
E.水肿
委托人在受托人按其委托要求成交后,必须如期履行交割手续,否则即为违约。