现在完成时 (The Present Perfect)
现在完成时由“have (第三人称单数has)+过去分词”构成。它主要有以下用法。
1. 表示过去发生的某一动作对现在造成的影响和结果，常和它连用的时间状语有 already, just, yet, never, ever, once, three times等.   例如：
I have just lost my pen; I am unable to do my exercises. 我的钢笔丢了；我没法作作业了。
I’ll not go to see the film tonight, because I have already seen it.我今晚不去看电影. 我已经看过了.

Have you watched the tennis match between Venus and her sister yet?你已经看了维纳斯和她妹妹之间的网球比赛么?
2. 现在完成时表示从过去某个时间开始到目前为止这段时间内反复发生的动作或多次出现的状态,要求时间状语是持续性的动词,常和它连用的时间状语有: for﹢一段时间 或 since﹢时间点， so far, by now, up till now, up to now, before等连用. 例如：
He has learned a good deal since he came to the new school. 他到新学校以来学到了不少东西。
We have planted many trees this year. 今年我们栽了很多树。
It has been 10 years since I last saw you. 我已经十年没有见到你了。

Up till now, I have already learnt 2000 new words.到目前为止,我已经学了2000个新单词.
3. 用在时间或条件的状语从句中，表示将来某时已经发生的动作，例如：
We’ll start at 5 p.m. if it has stopped raining by then. 我们五点钟动身，如果那时雨停了话。
I will give my opion when I have read the book through. 我把书看完了再提意见。

现在完成时和一般过去是的用法的比较。

1）  现在完成时在两个时间段上，一是过去，一是现在。尽管它所表示的动作发生在过去，但他必须在时间或意义上与现在有联系。 要么强调对现在的影响或结果，要么动作持续到现在。而一般过去时立足过去，仅指一个发生在过去的动作，与现在没有任何联系。

2）  一般过去时可以和表示过去的时间状语连用，而现在完成时一般不可以与表示过去的纯粹的时间状语连用。例如:

1.   Has he come?(主要问他现在是否在此地，强调结果)

Did he come?（主要问他是否曾经来过，问以前的情况，不涉及现在的情况）

2. He has injured his leg（强调腿现在是伤的，没有好）

He injured his leg.（强调腿受伤过这件具体的事，现在是好是坏，情况不明）

3. Chuck has gone to Nanjing（强调他现在不在这里）

Chuck went to Nanjing last week（强调具体的事，人现在在哪儿情况不明，无须告知）

 练习

1.“What happened in that new area?” “New parks ______ recently over there.”

A. are built  B. build C. have built D. have been built

2.“Did you wait for him very long?” “Yes, I ______ back home until10 p.m.”

A. did go   B. didn’t go   C. had gone   D. went

3.My maths teacher ______ my test.

A.       has not yet graded     B. has not yet been graded

C.   is not yet to be gradedD. is not yet graded

4.We ______ on it for many hours, but we have not yet come to any conclusion.

A. are being worked  B. are working   C. have been working    D. have been worked

5.She ______ a nurse’s work since she went into hospital.

A. is doing  B. has been doing    C. has done    D. has been done

6.I ______ the accident as if it happened yesterday.

  A. remembered           B. have still been remembering

    C. have remembered      D. still remember

7.We have sometimes accidents in this area, but no accidents ______ since last winter.

A. occur   B. have occurred  C. have been occurring    D. are occurring

8.I started my teaching career at the school more than twenty years ago, and I ______ there ever since.

A. was  B. had been   C. will be   D. have been

9.We ______ fine weather for the past few days.

A. have  B. are having  C. have been had   D. have had

10..It ______ every day so far this month.

A. is raining B. rains C. has rained D. has been rained

11.I shall tell you what he ______ at three o’clock this morning?

A.  had done  B. would do  C. was doing  D. had been done

12.How long ago ______smoking and drinking?

A. had you stopped   B. would you stop   C. did you stop  D. were you stopping

13.Up till now we ______ half the distance.

A. had only covered  B.have covered   C. would only cover   D. would be only covered

14.John told us that by the end of the year he and his wife ______ together for thirty years.

A. would have been living  B. would have lived   C. would have been lived  D. will have been living

15.I ______ to visit their country before long.

A. have been invited  B . am being invited   C. had been invited   D. shall be invited

16.Mr.Smith asked me if these islands ______ to Japan.

A. belong   B. are belonging    C. are belonged    D. have been belonged

17.Kepler proved that the sun ______ the center of the solar system.

A. is  B. was   C. had been   D. would be

18.This is one of the best film that ______ this year.

A. comes out  B. is coming out   C. has come out   D. have come out

19. “What were you doing when I phoned you?”

   “I had just finished my homework and ______ to take a bath.”

A      starting    B.to start   C. have started   D. was starting

20 “Have you gone to see the professor?”“No, but ______.”

A. I go   B. I am going to see   C. I go to see   D. I’m going to

21.My oral English teacher ______ in our college for fifteen years and does not want to leave.

A. worked    B. is working   C. works   D. has been working

22.. All the machines ______ so far

A. were repaired               B. would be repaired  

C.  have been repaired       D. were being repaired

23.This is the first time the students ______ to the Great Wall.

A. have gone   B. have been gone  C. have been going   D. are being gone

24. People are asked to make sure that they _________ the right cash before leaving the bank.

   A. will give     B. have been given       C. have given.     D. will be given.

25. I ____________ such kind of people before.

   A. had never seen    B. have never seen     C. saw     D. see