問題詳情:
I am sorry that I have kept you ________ me so long.
A ing B. to wait C ing for D wait for
【回答】
C 點撥:keep sb. doing sth.使某人一直做某事。wait 為不及物動詞,接名詞時需帶介詞for,故選C。
知識點:動詞和動詞短語
題型:選擇題