3．某些动词，例如：learn，lie，live，rain，sit，sleep，stand，study，wait，work等本身就有持续性，故常用于带有since或for的完成进行时，以及how long开头的疑问句中。

I've been sleeping for at least 8 hours，yet I still feel tired.

我已经睡了至少8个小时了，可还是觉得累。

How long have you been waiting here?

你在这儿等多久了。

以上的两个句子也可以使用现在完成时，可以说I've slept和have you waited。唯一的区别是，进行时形式更强调动作的持续性。

注意：(1)在强调指出动作还未结束，还要进行下去时，不能用现在完成时，而要用现在完成进行时，以避免使人误认为动作已经全部完成。

I've been writing the composition for two hours，but I haven't finished it yet.

这篇作文我写了两个小时，但还没写完。(强调动作没有结束，还要继续写下去)

I have been wanting to meet you for a long time.

和你见面是我盼望已久的事。

(2)有些动词，如live，play，rain，teach，study，wait等用于现在完成时并不表示动作已经完成，所以它们既可用于现在完成时，也可用于现在完成进行时，但如果强调动作延续时间的长久或带有感情色彩时，用现在完成进行时更好一些。

We have been playing football for nearly 3 hours.

我们已经踢了近三个小时的足球了。

Lisa has always been studying hard.

莉莎学习总是非常努力。(赞许的感情色彩)

(3)现在完成进行时有时也用来表示一种从以前到现在这个阶段反复发生的事。

I have always been thinking of her but I can't see her.

虽然我一直在想着她，但是我不能见她。

[高考链接2]

Ⅰ.用所给动词的正确形式填空

1．I have read(read) half of the English novel，and I'll try to finish it at the weekend.(2016·北京)

2．In my hometown，there is always a harvest supper for the farmers after all the wheat has been cut(cut)．(2015·重庆)

3．-Where is Peter？I can't find him anywhere.

-He went to the library after breakfast and has been writing(write) his essay there ever since.(2015·福建)

4．Despite the previous rounds of talks，no agreement has been reached(reach) so far by the two sides.(2015·天津)

5．In the last few years，China has made(make) great achievements in environmental