Question

to be doing和to have been doing都是什么意思???(求助中……有这个用法吗？)

举个例子呢？？？（感谢）
to be doing 不是不定式表将来吗？

Answer 1

to be doing正在做某事 (其实就是现在进行时)
to have been doing过去正在做某事,现在还在做(通常表示延续)
当实际用的时候,to没有任何实际意义,所以这两个结构可以简写成:be doing,have been doing.

例:I'm singing(我在唱歌)
She has been playing the piano for 5 years.(她已经弹了5年钢琴).(她以前在弹,现在还准备弹下去).

不定式表将来是:going to do sth.
例:I'm going to have a good sleep.(我要好好睡一觉).

be doing也可以表将来,"进行时表将来.
例:She is flying to England in a week.(她一周后要飞往英国)

Answer 2

to be doing正在做某事
to have been doing过去正在做某事

Answer 3

见过pretend to be doing 假装正在做什么 见过 have been
doing 一直在做什么