it doesn't matter whether you use MAY or MIGHT, but we use only MIGHT when the situation is not real!
e.g. If I knew them better, I might invite them to dinner. (查看原文)
Unit 10.Present perfect continuous and simple(I have been doing and I have been done.)
Present perfect continuous:We are interested in the activity. It does not matter whether something has been finished or not.
Present perfect simple: The important thing is that something has been finished.
Examples:
My hands are very dirty. I've been repairing the car. The car is OK again now. I've repaired it.
We use the continuous to ask or say how long(for an activity that is still happening):
How long have you been reading that book?
We use the simple to ask or say how much, how many or how many times(completed actions):
How many pages of that book have you read?
*There are some verbs(for example, know/like/believe)that are normally not used in the continuous. (查看原文)
Unit 11 How long have you(been)...?
A.Compare the present and the present perfect:
*Amy is in hospital.
But she has been in hospital since Monday.(not "Amy is in hospital since Monday.")
*We know each other very well.
but We have known each other for a long time.
B.I have been doing something(present perfect continuous)=I started doing sth. in the past and I am still doing it(or have just stopped):
*I've been learning English for a long time.
*Sorry I'm late. Have you been waiting long?
C.I have done(simple) or I have been doing (continuous)
The continuous is more usual with how long, since and for.
You can normally use either the continuous or simple with live and work:
How long have you been working/have you worked here?
but we use the simple with always:
* John has always lived in Lo... (查看原文)
Unit 12. When...? and How long...? For and since
A.Compare When...?(+past simple) and How long...?(+present perfect):
--When di it start raining?
--It started raining an hour ago/at 1 o'clock
--How long has it been raining?
--It's been raining for an hour/since 1 o'clock.
B.We use both for and since to say how long something has been happening.
We use for when we say a period of time(two hours,six weeks etc.):
*I've been waiting for two hours.
two hours ago-> now
We use since when we say the start of a period(8 o'clock,Monday,1988 etc.):
*I've been waiting since 8 o'clock.
8 o'clock->now
*They haven't had a holiday for ten years.(you must use for)
We do not use for + all...(all day/all my lift etc.):
*I've lived here all my life.
C.We say It's(a long time/two years e... (查看原文)
Unit 13 Present perfect and past(1)(I have done and I did)
A.Tom is looking for his key.He can't find it.
He has lost his key.
This means that he doesn't have his key now.
Ten minutes later:
Now Tom has found his key. He has it now.
Has he lost his key?
No,he hasn't.He has found it.
Did he lose his key?
Yes, he did.
He lost his key(past simple)
but now he has found it.(present perfect.)
The present perfect is a present tense.It always tells us something about now. Tom has lost his key=he doesn't have his key now.
The past simple tells us only about the past.If somebody says "Tom lost his key", we don't know whether he has it now or not. We only know that he lost it at some time in the past.
B.Do not use the present perfect if there is no connection with the present(for example, things t... (查看原文)
Unit 14.Present perfect and past(2)(I have done and I did)
A.Do not use the present perfect(I have done)when you talk about a finished time.(for example,yesterday/ten minutes ago/in 1985/when i was a child.).Use a past tense:
*The weather was nice yesterday.
*They arrived the minutes ago.
Compare:
Present perfect
*Tom has lost his key. He can't get into the house.
Here, we are not thinking of the past action. We are thinking of the present result of the action:Tom doesn't have his key now.
Past simple
*Tom lost his key yesterday.He couldn't get into the house.
Here, we are thinking of the action in the past. We don't know from this sentence whether Tom has his key now.
B.Compare present perfect and past:
* I've done a lot of work today.
We use the present perfect for a period of time t... (查看原文)
Unit 15. Past perfect(I had done)
A.I/we/they/you/it had(=I'd etc.)gone/finish etc.
The past perfect simple is had+past participle(gone/seen/finished etc.)
This is the starting poinit of the story. Then, if we want to talk about things that happened before this time,we use the past perfect(had...):
*When Sarah arried at the party, Paul had already gone home.
B.Had done(past perfect)is the past of have done(present perfect).Compare:
present perfect
* Who is that woman? I've never seen her before.
past perfect
*I didn't know who she was.I'd never seen her before.(=before that time)
C.Compare the past perfect(I had done) and past simple(I did):
* Was Tom at the party when you arried? No,he had already gone home.
but "Was Tom there when you arried?""Yes, but he went home soon afterwards.... (查看原文)
作者: Raymond Murphy 副标题: A Self-Study Reference and Practice Book for Intermediate Learners of English isbn: 052118939X 书名: English Grammar in Use with Answers and CD-ROM 页数: 392 定价: GBP 29.57 出版社: Cambridge University Press 装帧: CD-ROM 出版年: 2012-2-23
