题目

--- The light in the office is still on.    --- Oh, I forgot _______.A. turning it off  B. turn it off   C. to turn it off    D. having turned it off 答案：C 解析: forget to do sth忘记（要）做某事。1．一批服装由甲单独做需30天才能完成，由乙单独做需20天完成．甲、乙合干需要多少天能完成？