清洁保养含有两个方面的内容，一为清洁，即（），二是保养，即保护调养使之保持正常状态。

A、去除尘土

B、油垢

C、污渍

D、拖尘

He does help others, but he always expects returns ____. As a result, nobody will accept anything from

him. [ ]

A. at no time

B. in no time

C. for no time

D. after no time