has have had
当主语是（I, we, they）时用have，当主语是第三人称he, she, it 时用has
had 是has和have的过去式。
用法：
1、后接过去分词，构成现在和过去完成、完成进行时。例如：
a) He has gone to Beijing. 他已经到北京去了。
b) I have been a teacher since then. 从那时起我就一直当教师。
c) They had left when I got there. 我到那里的时候，他们已经走了。
d) He has been working hard since early morning. 丛一大早他就一直在下劲干活。
2、has have had也可以作为一般动词，意为“拥有”“进行”“吃”“使得”“让”等。如果后接不定式，意为“不得不”。因为它们不是特殊动词，所以不能在它们后面加not构成否定句，不能把它们移到句首构成疑问句。例如：
a) He has a good pen. 他有一支好笔。
b) We have supper at 6:00. 我们六点钟吃晚饭。
c) I had my hair cut yesterday. 我昨天理了发。（我让我的头发被剪了，昨天）
d) I have to leave now. 我得走了。