肯定句：主语+have/has+过去分词

否定句：主语+have/has not +过去分词

疑问句：Have/Has+主语+过去分词

7. 现在完成时

(1) 现在完成时的句型结构

①肯定句：主语+ have/has+ 过去分词

②否定句：主语+ have/has+ not+过去分词

③疑问句：Have/Has +主语+过去分词

(2) 现在完成时的用法

①表示到目前为止曾经有过的或未曾有过的经历和体验。常和never, ever, several times等连用。

如：

I’ve never been to Africa.

Have you ever been to Tokyo?

I’ve been there three times.

②. 表示某动作从过去开始，现在刚刚完成，对现在有一定的影响。常与just, already, yet, so far等词语连用。

如：

He has just finished his new book.

注意：just now用于过去时。

③.表示某动作从过去开始，一直持续到现在，可能还会持续下去。通常与for或since连用。

如：I have lived in Qingdao for 6 years. /since 6 years ago/since 2003/since I came to this city.

It is/has been …+ since….

It’s been seven years since we last saw each other.

It’s six years since he was a teacher.

注意:for+一段时间，since后接一个过去的时间点或一般过去时的句子。

④ 在表将来的时间状语和条件状语从句中代替将来完成时。

如：

You can go home when you have finished your work.

比较：You can go home when you finish your work.

(3) 过去分词的构成

① 一般情况下在动词词尾后直接加-ed。

如：

listen-listened, talk-talked

② 以不发音的字母e结尾的动词，直接加-d。

如：

live-lived, hope-hoped

③ 以辅音字母加y接尾的动词，y变i，再加-ed.

如：

worry-worried, hurry-hurried

④ 以重读闭音节结尾，且结尾只有一个辅音字母的动词，双写辅音字母，再加-ed。

如：

drop-dropped, plan-planned, stop-stopped

⑤ 不规则变化

如：

cut-cut-cut, come-came-come

begin-began-begun, lend-lent-lent