I waited for Mrs Brown for twenty minutes【用现在完成进行时态改写句子】 I [ ] [ ][ ]for Mrs Brown

题目

I waited for Mrs Brown for twenty minutes【用现在完成进行时态改写句子】 I [ ] [ ][ ]for Mrs Brown
I waited for Mrs Brown for twenty minutes【用现在完成进行时态改写句子 I have been waiting for Mrs Brown【 】twenty minutes

答案

have been waiting
现在完成进行时的基本结构为：have /has been doing...
I've been waitig for Mrs Brown for twenty minutes.