第4章 现在完成时
现在完成时：用来表示之前已发生或完成的动作或状态，其结果和现在有密不可分的联系。
现在完成时的构成
现在完成时的用法
1. 表示说话之前已经完成的动作，而且这个动作的结果对现在仍然有影响。
It seems that I have met him somewhere before.
似乎我以前在哪里见过他。
The manager has just left. If only you had come a moment earlier.
经理刚走。你要是早点来就好了。
Where have you been this morning? We were all anxious about you.
今天上午你去哪里了？我们都很担心你。
He has been to the city before，so he knows the way well.
他以前去过那个城市，所以他很熟悉那里的路。
★常用的时间状语：already，yet，now，just，by the time，never，ever，twice等。
2. 表示过去已经开始，持续到现在，而且还可能继续下去的动作或状态。
I have travelled to most of the cities in China since five years ago.
五年来我已游遍了中国的大多数城市。
I have worked in the company since I graduated from university.
大学毕业以后，我一直在这家公司工作。
We have learned about 3，000 words in the past few years.
在过去的几年中，我们已经掌握了大约三千个词汇了。
★ 常用的时间状语：today，this morning，recently，lately，all my life，all the time，all day，so far，in the past/last…，since then，for a long time等。
3. 在时间和条件状语从句中，用来代替将来时。
Once you have made a promise，you shouldn't break it.
一旦许下诺言，你就不能违背。
I'll go home as soon as I have finished all my homework.
我一做完所有作业就回家。
要点拓展
1. 用于现在完成时的句型。
① It/This is the first/last/only…that…结构中的从句部分用现在完成时。
It is the first time that I have visited the city.
这是我第一次拜访这个城市。
It is the third time that the boy has been late.
这是这个男孩第三次迟到。
This is the only book that he has ever written.
这是他写过的唯一的一本书。
② 在“It/This is+形容词最高级+that…”结构中，that从句要用现在完成时。
This is the best film that I've seen. 这是我看过的最好的电影。
It is the most interesting book that I have ever read.
这是我读过的最有趣的书。
2. 瞬间动词和持续性动词在现在完成时中的用法。
瞬间动词的肯定形式通常不能与表示一段时间的for短语、since短语或从句等连用，因为瞬间动词不能表示延续的状态，它只能用现在完成时表达“已经做了”或“还没有做”，而不能表达“持续了多久”，但是在否定句中就没有这个限制了。
瞬间动词的否定形式可以与表示延续时间的状语连用，即动作不发生的状态是可以持续的。
（错）I have received his letter for a month.
（对）I haven't received his letter for almost a month.
我已经将近一个月没收到他的信了。
★ since从句中用持续性动词，表示该动作已经结束。
I haven't heard from her since she left Shanghai. 自从她离开上海以来，我就没收到她的信。（She left Shanghai这个动作结束）
It has been several weeks since I was ill.
我病好了好几周了。（I was ill这个动作结束后）
3. since和for经常出现在现在完成时的句子中，但需要注意以下用法。
since用来说明动作起始时间，for用来说明动作延续的时间长度。
I have lived here for more than twenty years.
我已经在这里住了二十几年了。
I have lived here since I was born. 自从我出生，我就住在这里。
My aunt has worked in the clinic since 2000.
我阿姨从2000年开始就一直在这家诊所工作。
I have known her since she was a little girl.
从她还是个孩子时起，我就认识她。
My brother has been in the Youth League for five years.
我哥哥加入青年团已经有五年了。
I have not heard from my uncle for a long time.
我已经很久没有收到叔叔的来信了。
★ 并非有for作为时间状语的句子都用现在完成时。
I worked here for more than twenty years.
我曾经在这里工作了20多年。（我现在已不在这里工作）
I have worked here for many years.
我已经在这里工作了多年。（现在我仍在这里工作）
4. 一般过去时和现在完成时的区别。
① 一般过去时所表示的一个或一段过去时间是可以具体确定的，与其他时间没有牵连。过去时表示的是对过去事实的描述，与现在的情况没有关系。现在完成时表示的事情发生在不能具体指出的过去某个或某段时间，它表示和现在情况有关系，是过去发生的事情在现在产生的结果或对现在的影响，或动作一直持续着。
Did you go to Europe last year?去年你去欧洲了吗？（对去年发生的行为的疑问）
Have you been to Europe? 你去过欧洲吗？（表示过去某个时间发生的行为，实际上问的是现在的情况，即，你对那里了解多少?）
②表示确定的过去时间的状语可以和一般过去时连用，但不能用于现在完成时。能用于现在完成时的是在一定意义上与现在时间有关系的时间状语。
I have been to Europe twice. 我去过欧洲两次了。
He went to Europe last week. 他上周去欧洲了。
③像fall，arrive，come，leave，start，buy，sell，hear，join等瞬间动词，可以用一般过去时，但用现在完成时则不能和表示一段时间的状语连用。
How long have you bought the car?（×）（buy是瞬间动词，不能和how long连用）
How long have you had the car？（√）这辆车你买了多久？
He has fallen ill for a week.（fall ill是瞬间动词，不能和“for+一段时间”连用）
He has been ill for a week.（√）他已经病了一个星期了。
专项训练
1. The unemployment rate in this district__________from 6% to 5% in the past two years.
A. has fallen
B. had fallen
C. is falling
D. was falling
答案：A in the past two years是明确的现在完成时的标志。
2. The first use of atomic weapons was in 1945，and their power__________increased enormously ever since.
A. is
B. was
C. has been
D. had been
答案：C ever since表示核武器的威力从1945年至今变得越来越强大，用现在完成时。
3. Although he has lived with us for years，he__________us much impression.
A. hadn't left
B. didn't leave
C. doesn't leave
D. hasn't left
答案：D 表示之前的动作对现在造成的影响。
4. Danny__________hard for long to realize his dream and now he is popular.
A. works
B. is working
C. has worked
D. worked
答案：C 表示之前的动作对现在造成的影响。
5. They__________two free tickets to Europe；otherwise they'd never have been able to afford to go.
A. had got
B. got
C. have got
D. get
答案：C 强调“已经得到票”这个结果，强调对现在事实的影响。
6. Although medical science__________control over several dangerous diseases，what worries us is that some of them are returning.
A. achieved
B. has achieved
C. will achieve
D. had achieved
答案：B “尽管医学科学已经控制了一些严重的疾病”，强调现在的结果。
7. My friend，who__________on the International Olympic Committee all his life，is retiring next month.
A. served
B. is serving
C. had served
D. has served
答案：D 表示过去已经开始，持续到现在，而且还可能继续下去的动作或状态。
8.__________my sister three times today but her line was always busy.
A. I'd phoned
B. I've been phoning
C. I've phoned
D. I was phoning
答案：C three times today强调动作发生的结果和对现在造成的影响。
9. He was hoping to go abroad but his parents__________that they won't support him unless he can borrow money from the bank.
A. were deciding
B. have decided
C. decided
D. will decide
答案：B 尽管这里没有明确的时间状语，但从后面的they won't support him可以看出，这里的现在完成时是为了强调现在的结果。
10. The coffee is wonderful！It doesn't taste like anything I__________before.
A. was having
B. have
C. have ever had
D. had ever had
答案：C 这里的现在完成时是为了强调现在的事实“这咖啡真不错”。
11. John and I__________friends for eight years. We first got to know each other at a Christmas party. But we__________each other a couple of times before that.
A. had been；have seen
B. have been；have seen
C. had been；had seen
D. have been；had seen
答案：D have been friends for eight years表示过去已经开始，持续到现在，而且还可能继续下去的状态。had seen each other这个过去完成时是由before that决定的。
12. — Do you know our town at all?
— No，this is the first time I__________here.
A. was
B. have been
C. came
D. am coming
答案：B this is the first time这个句型中要用现在完成时。
13. Great changes__________in my hometown in the past few years.
A. were taken place
B. have been taken place
C. took place
D. have taken place
答案：D in the past few years是明确的现在完成时的标志，而且take place没有被动的用法，所以B不对。
14. — Why does Mary look to be so sorry?
— Because she__________by her classmates.
A. has been laughed
B. has laughed at
C. was laughed
D. has been laughed at
答案：D 表示已经发生的动作对现在造成的影响，laugh at要用被动形式，表示她被嘲笑的事实。
15. Professor James will give us a lecture on the Western culture，but when and where__________yet.
A. hasn't been decided
B. haven't decided
C. isn't being decided
D. aren't decided
答案：A 表示“还没有决定”现在的结果，而且必须用被动形式。
16. She has set a new record，that is，the sales of her latest book__________50 million.
A. have reached
B. has reached
C. are reaching
D. had reached
答案：A sales是“销售额”的意思，动词用复数。这里的have reached强调对现在造成的结果和影响。
17. — We haven't heard from Jane for a long time.
— What do you suppose__________to her?
A. was happening
B. to happen
C. has happened
D. having happened
答案：C do you suppose是插入语，has happened说明过去发生的事情对现在事实造成的结果。
18. When I was at college I__________three foreign language，but I__________all except for a few words of each.
A. spoke；had forgotten
B. spoke；have forgotten
C. had spoken；had forgotten
D. had spoken；have forgotten
答案：B When I was at college表示对过去事实的陈述，“but”后的句子说明了现在的状态。
19. — How are you today?
— Oh，I__________as ill as I do now for a very long time.
A. didn't feel
B. wasn't feeling
C. don't feel
D. haven't felt
答案：D “我很久没有像现在这么难受了。”为了强调现在的状态。
20. I wonder why Jenny__________us recently. We should have heard from her by now.
A. hasn't written
B. doesn't write
C. won't write
D. hadn't written
答案：A recently表示最近的动作对现在造成的影响。