We haven't seen each other for ten years.

　　They have grown such a lot since we last saw them.

　　So far/Up to now, Timson has made 13 films.

　　I've written three letters this morning. (=it is still morning)

3 现在完成时可以用在条件或时间状语从句中, 表示将来某个时刻之前已经完成的动作。

　e.g. I'll go home as soon as I have finished my homework.

Please lend me that book if you have finished reading it.

4.表示从过去某一时间到说话这段时间反复发生的动作或多次动作的总和，常与频度副词always, often, seldom, never等连用。

　　I 've often heard such news.

　　I 've been to Beijing.

(二) 使用现在完成时的句型

　　1) 现在完成时+since + 点时间状语(名词、短语、从句, 其中从句用一般过去时)

　　2) 现在完成时+ for+ 段时间状语

　　3) It / This is the first /其它序数词/ last time + that 从句中, 从句使用现在完成时。

　　注意: 在下面的句子中, 主句的谓语动词常用一般现在时：

　　It is three years since I began to work on the farm.

　　It's a long time since I saw you last.

(三)现在完成时与一般过去时的区别:

　现在完成时表示某一已经完成的动作对现在造成的结果或影响, 强调的是现在的情况, 所以不能与表示过去的时间状语连用; 一般过去时只表示某一动作或状态在过去发生或存在过, 与现在不发生联系, 它可以与表示过去的时间状语连用。

He has read that book. (说明他现在知道那本书的内容)

He read that book last year. (只说明他去年读过那本书 )

He has gone to America. (他现在不在此地, 在美国)

He went to America. (只说明他去过美国)

(四) 终止性动词与延续性动词：

　　1. 终止性动词: 表示短暂的运动状态,不能和表示一段时间的状语连用,常用的动词有: come, go, start, begin, leave, arrive, reach, get, get up , join, marry, open, close, give, lend, borrow, finish, break, see, hear, notice, find, understand, die 等。

　　2. 延续性动词: 表示长时间的运动状态,能和表示一段时间的状语连用。

　　常用的动词有: live, study, work, teach, stay, read, play, fly, talk, rain, eat, run等

当堂检测：

用所给词的适当形式填空

(1)So far this year I more than twenty articles and I'll try my best to write more.(publish)

(2)- you him around the museum yet？(show)

　-Yes. We had a great time there.

(3)With the help of experienced career instructors，this type of job­hunting training

_ to be very efficient.(prove)