1、have的过去式和过去分词都是had，但是具体应用有区别。

2、1. 表示过去用过去式：We had a meeting yesterday .(发生在过去)。

3、2. 表示现在完成（助动词的现在式+过去分词）：We have had a meeting just now.(虽然发生在过去，却对现在产生了影响，即会议的进程在说话时依然清晰可见)。

4、3. 表示过去完成（助动词的过去式+过去分词）：We told him we had had a meeting the day before yesterday.（发生在told的过去，即过去的过去）。

5、hasThis is a clear demonstration of how technology has changed?这清楚地表明了技术已有了怎样的进步。

6、2、There has already been a definite improvement?已经有了显著的改进。

7、3、The committee has been dissolved?委员会已经解散了。

8、4、She enchanted you as she has so many others.她迷住了你，就像她迷住了其他那么多人一样。

9、5、The conflict with James has dragged on for two years.与詹姆斯的冲突拖了两年。

10、have的过去式和过去分词都是had，但是具体应用有区别。

11、1. 表示过去用过去式：We had a meeting yesterday .(发生在过去)2. 表示现在完成（助动词的现在式+过去分词）：We have had a meeting just now.(虽然发生在过去，却对现在产生了影响，即会议的进程在说话时依然清晰可见)3. 表示过去完成（助动词的过去式+过去分词）：We told him we had had a meeting the day before yesterday.（发生在told的过去，即过去的过去）have原型had过去式We had some guests for dinner last night. 我们昨晚请了几位客人吃饭。

12、We had a wonderful time on the beach. 我们在海滩上玩得好极了。

13、had过去分词 They had already had breakfast before they arrived at the hotel.have的过去式和过去分词都是had过去式：I had some problems yesterday.过去分词不好造例句。

14、这就是传说中最最标准的十五个字。