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  • substances一看就是复数啦,当然是have

    这是时态问题,这里是现在完成时,你选的是过去完成时

    ps:现在完成时 have∕has + P.P.

    ⑴ 与just连用,表示刚刚完成的动作或状态(just放在have∕has与P.P.之间).

    I have just had lunch.

    He has just finished his homework.

    ⑵ 表示动作发生在过去,持续到现在,有可能延续到将来,常与since“自从…”(后面跟一点时间)for(后面跟一段时间)连用.

    I have learned English since 2000.

    He has lived there for 10 years.

    ⑶ 表示过去的动作对现在的影响.

    He has lost his key.

    ⑷ 与最高级连用,表示“到目前为止最…”

    You’re the cleverest girl that I’ve seen.

    ⑸ 与It∕This the first time that…连用,表示“第一次……”

    It∕This is the first time that he has learned English.

    ⑹ have∕has been to…曾经去过…(已经回来了)

    have∕has gone to…去了…(还没回来)

    I have been to Shanghai.

    Tom has gone to Shanghai.

    ⑴单数第三人称:

    肯:S.三 + has + P.P.+…

    否:S.三 + has not (hasn’t) + P.P.+…

    肯疑:Has + S.三 + P.P.+…?

    Yes,S.三 + has.

    No,S.三 + hasn’t.

    否疑:Hasn’t + S.三 + P.P.+…?

    Yes,S.三 + has.

    No,S.三 + hasn’t.

    ⑵其他人称:

    肯:S.+ have + P.P.…

    否:S.+ have not ( haven’t ) + P.P.…

    肯疑:Have + S.+ P.P.

    Yes,S.+ have.

    No,S.+ haven’t.

    否疑:Haven’t + S.+ P.P.

    Yes,S.+ have.

    No,S.+ haven’t.

    过去完成时 had + P.P.

    ⑴ 动作发生在过去的某一时间之前,持续到过去的这一点,有可能延续到将来.By the end of last year ,I had lived here for 20 years .

    ⑵ 动作在过去的某一时间已经完成.

    He had finished his homework before his mother came in .

    ⑶ 动作常用于间接引语中,表示某事在我们过去所谈话或者所思考的时间以前已经发生了.Tom said that he had been to about 30 countries .

    肯:S.+ had + P.P.+…

    否:S.+ had not (hadn’t )+ P.P.+…

    肯疑:Had + S.+P.P.+…?

    Yes,S.+ had.

    No,S.+ hadn’t.

    否疑:Hadn’t + S.+ P.P.+…?

    Yes,S.+ had.

    No,S.+ hadn’t.

    现在完成进行时 have∕has + been + V-ing

    ⑴表示从过去开始一直持续到在,这个动作可能刚刚结束,也可能还要持续下去,这种时态动作是连续的,没有中断过.

    I have been teaching for about 10 years .

    He has been smoking for 30 years .

    ⑵表示一直到说话为止的一段时间内一再重复的动作.

    What have you been doing these years

    ⑶表示一直到说话为止的一段时间内,大部分时间都在持续进行的动作(不一定持续到说话的时候)往往暗示这个动作对现在的影响.

    I have been working in that bank for 5 years .

    肯:S.+ have∕has + been + V-ing…

    否:S.+ haven’t ∕hasn’t + been + V-ing…

    肯疑:Have∕Has + S.+ been + V-ing…?

    Yes,S.+ have∕has

    No,S.+ haven’t ∕hasn’t

    否疑:Haven’t ∕Hasn’t + S.+ been + V-ing…?

    Yes,S.+ have∕has

    No,S.+ haven’t ∕hasn’t