题目

The play had already been on for quite some time when we _______ at the New Theatre.   A. have arrived              B. arrived              C. had arrived                D. arrive 答案：B已知a∈R，则“a＞2”是“a2＞2a”成立的（　　） A、充分必要条件B、必要而不充分条件C、充分而不必要条件D、既不充分也不必要条件