has是have的第三人稱單數(shù)形式，比如he，she就要用has，而I，we，they要用have。針對(duì)had來說，have和has是現(xiàn)在時(shí)，had則是has和have的過去式。

have、had、has的用法和區(qū)別：

1、have、had、has區(qū)別在于不同時(shí)態(tài)和不同人稱之間，三個(gè)單詞其實(shí)表達(dá)為一個(gè)意思。

2、如果是一般現(xiàn)在時(shí)，第三人稱單數(shù)的時(shí)候用has，其它（如第一人稱和第二人稱）用have。

3、如果是一般過去時(shí)，全部都用had。

4、has/have been是現(xiàn)在完成時(shí)，has用于第三人稱單數(shù)，had been過去完成時(shí)，跟前者相比，比前者更為過去。

have

1、Alex has already gone

亞歷克斯已經(jīng)走了。

2、When I met her, she had just returned from a job interview

我遇見她時(shí)，她剛參加完一場(chǎng)求職面試回來。

3、You haven't sent her away, have you?

你還沒有把她送走，是嗎？

4、He arrived in San Francisco, having left New Jersey on January 19th

1月19日離開新澤西后，他到了舊金山。

5、I went out and had a walk around

我出去在周圍散了一會(huì)兒步。

had

1、Had he succeeded, he would have acquired a monopoly

要是他當(dāng)時(shí)成功了，他就會(huì)取得壟斷地位。

2、If your customer thinks he's been had, you have to make him happy.

要是顧客感覺自己當(dāng)了冤大頭，你就得設(shè)法讓他消氣。

3、Unless she loses some weight, she's had it

除非她減點(diǎn)兒肥，否則她就沒戲了。

4、I've had it. Let's call it a day

我受不了了。今天就到這兒吧。

5、Had I known what the problem was, we could have addressed it.

如果我當(dāng)時(shí)知道問題出在哪里，我們就可以設(shè)法解決了。