Withthehelpofhightechnology,moreandmorenewsubstancesinthepastyears.为什么用havebeendiscovered而不是hasbeendiscovered不是past—youhimaroundthemuseumyet?(2007江苏)—Yes.Wehadagreattimethere

Question

With the help of high technology,more and more new substances _____ in the past years.
为什么用have been discovered 而不是has been discovered
不是past
—______ you ______ him around the museum yet?(2007江苏)
—Yes.We had a great time there.
A.Have ; shown B.Do ; show C.Had; shown D.Did; show
为什么是A
可以是had been discovered?

Answer 1

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