1．Dashan，who has been learning(learn) crosstalk，the Chinese comedic tradition，for decades，wants to mix it up with the Western stand­up tradition.(2016·江苏)

2．Marty has been working(work) really hard on his book and he thinks he'll have finished it by Friday.(2015·陕西)

3．Since the time humankind started gardening，we have been trying(try) to make our environment more beautiful.(2014·湖南)

4．-Tony，why are your eyes red?

-I have been cutting(cut) up peppers for the last five minutes.(2014·江西)

Ⅱ.单句改错(每小题仅有1处错误)

1．The early morning barking have been disturbing us as we are often up all night with the baby.(2014·辽宁，短文改错)

have→has

2．My teachers have been telling me how great my writing was.(2010·全国I，短文改错)

have→had

二、现在完成时与现在完成进行时

现在完成时和现在完成进行时均可表示"从过去开始一直持续到现在"的动作，有时两者可换用。这两种时态的主要差别有两个：

现在完成时 现在完成进行时 表示动作已完成 表示动作在迄今为止的一段时间内曾经延续进行或目前仍在继续 强调动作的结果 强调动作持续进行的状态 1.多数情况下两种时态不可换用

在表示"从过去开始一直持续到现在"这个概念时，现在完成时多用于口语。如果侧重动作的结果，多用现在完成时；如果侧重动作的延续性或者动作仍然继续下去时，由于现在完成进行时还带有进行时的持续性、暂时性和未完成性，这时宜采用现在完成进行时，而且不能与现在完成时交换使用。

I have read this book.

我读过这本书。(动作已经完成)

I've been reading this book.

我一直在读这本书。(动作还将继续下去)

2．状态动词、知觉动词或情感动词，例如：see，feel，know，love等，不可用于现在完成进行时，但可用于现在完成时。

I have known him for years.

我认识他已经好几年了。

不可说成：I have been knowing him for years.