3)现在完成时不能和明确指出时间的状语，如yesterday, last year, in 1976, two days ago, just now, when I came in 等连用， 但可以和不明确指出时间的状语，如already, yet, sometimes, always, often, before, lately, recently, once, twice, ever,
never等连用。例如：
She has already come. 她已经来了。
I haven’t read it yet. 我还没读过这个。
I have met him before. 我从前曾见过他。
Ma Hong has always been a good student. 马红一直是个好学生。
I have often seen him in the street. 我经常在街上看见他。
They have never been to Yan’an. 他们从未去过延安。
I haven’t seen him lately. 我近来没看到他。
翻译练习：
1)他们已经答复了我们的信。
They have already answered our letter.
2)自去年以来我就未遇见过王英。
I haven’t met Wang Ying since last year.
3)他刚把他的名字告诉我。
He has just told me his name.
4)你到过杭州吗? 到过。我一个月以前去过那里。我去过两三次。
Have you ever been to Hangzhou? Yes, I have. I went there a month ago.
I have been there two or three times.
5)他在海外住了很长时间了。
He has lived abroad for a very long time.
4、现在完成进行时
(1)构成：第三人称单数由has been + 动词的现在分词;其他人称和数由have been + 动词的现在分词。
(2)用法：
1)表示动作从过去开始一直延续到现在，可能刚刚终止，也可能仍然在进行。
I’ve been waiting for you since eight o’clock in the morning. 我从早上8点钟一直在等你。
It has been raining for three hours. 雨一直下了三个小时了。
What book have you been reading recently? 最近你一直在读什么书?
2)有些动词不能用于现在进行时，如be, have, like, love, know, see, hear等，这些词同样也不能用于现在完成进行时。如：
I haven’t seen you for ages. 我好久没见到你了。
I have loved her for a long time. 我一直爱她。
I have known him for a long time. 我认识他很久了。
3)现在完成时表示到现在为止已经完成的动作，强调结果;而现在完成进行时强调动作的持续性，强调“一直”，往往表示动作仍未结束。如：
I have been reading this novel. 我一直在读这本小说。(我仍然在读)
I have read two novels. 我已读过两本小说。(可能刚读过，也可能很久以前读的)
I have been writing letters. 我一直都在写信。
I have written three letters. 我已经写完三封信了。
Now we have cleaned the room, we can move the things in. 既然我们已经打扫完房间，我们可以把东西搬进来了。
We’ve been cleaning the classroom, but we haven’t finished yet. 我们一直在打扫教室，但还没干完。