We use could in a number of ways. Sometimes could is the past of can:
* Listen. I can hear something. (now)
* I listened. I could hear something. (past)
But could is not only used in this way. We also in the future (especially to make a suggestion). For example:
* A: What shall we do this evening?
B: We could go to the cinema.
* It's a nice day. We could go for a walk.
* When you go to New York next month, you could stay with Barbara.
* A: If you need money, why don't you ask Karen?
B: Yes, I suppose I could.
Can is also possible in these sentences ('We can go for a walk,' etc.). Could is less sure than can. You must use could (not 'can') when you don't really mean what you say. For example:
* I'm so angry with him. I could kill him! (not 'I can kill him')
We also use could to say that something is possible now or in the future:
* The phone is ringing. It could be Tim.
* I don't know when they'll be here. They could arrive at any time.
Can is not possible in these examples (not 'It can be Tim')
In these sentences could is similar to might:
* The phone is ringing. It might be Tim.
Compare could (do) and could have (done):
* I'm so tired. I could sleep for a week. (now)
* I was so tired. I could have slept for a week. (past)
Most often, we use could have (done) for things which were possible but did not happen:
* Why did you stay at a hotel when to New York? You could have stayed with Barbara. (= you had opportunity to stay with her but you didn't)
* Jack fell off a ladder yesterday but he's all right. He's lucky - he could have hurt himself badly. (but ha didn't hurt himself)
* The situation was bad but it could have been worse.
Sometimes could means 'would be able to...':
* We could go away if we had enough money.(= we would be able to go away)
* I don't know how you work so hard. I couldn't do it.
Could have (done) = would have been able to (do):
* Why didn't Liz apply for the job? She could have got it.
* We could have gone away if we'd had enough money.
* The trip was cancelled last week. Paul couldn't have gone anyway because he was ill. (= he wouldn't have been able to go)
* You did very well to pass the exam. I'm sure I couldn't have passed it. (= I wouldn't have been able to pass it if I had taken it)
EXERCISES
27.1 Answer the questions with a suggestion. Use could.
1. Where shall we go for our holidays? (to Scotland) We could go to Scotland.
2. What shall we have for dinner tonight? (fish) We ---
3. What shall I give Ann for her birthday? (a book) You ---
4. When shall I phone Angela? (now) ---
5. When shall we go and see Tom? (on Friday) ---
6. Where shall we hang this picture? (in the kitchen) ---
27.2 Put in can or could. Sometimes either word is possible.
1. 'The phone is ringing. Who do you think it is?' 'It _could_ be Tim.'
2. I'm really hungry. I --- eat a horse!
3. If you're very hungry, we --- have dinner now.
4. It's so nice here. I --- stay here all day but unfortunately I have to go.
5. 'I can't find my bag. Have you seen it?' 'No, but it --- be in the car.'
6. Peter is a keen musician. He plays the flute and he --- also play the piano.
7. 'What shall we do?' 'There's a film on television. We --- watch that.'
8. The weather is nice now but it --- change later.
27.3 Complete the sentences. Use could or could have + a suitable verb.
1. A: What shall we do this evening?
B: I don't mind. We _could go_ to the cinema.
2. A: I had a very boring evening at home yesterday.
B: Why did you stay at home? You --- to the cinema.
3. A: There's an interesting job advertised in the paper. You --- for it.
B: What sort of Job is it? Show me the advertisement.
4. A: Did you go to the concert last night?
B: No. We --- but we decided not to.
5. A: Where shall we meet tomorrow?
B: Well, I --- to your house if you like.
27.4 Read this information about Ken:
Ken didn't do anything on Saturday evening.
Ken was short of money last week.
Ken doesn't know anything about machines.
Ken's car was stolen on Monday.
Ken was free on Monday afternoon.
Ken had to work on Friday evening.
Some people wanted Ken to do different things last week but they couldn't contact him. So be didn't do any of these things. You have to say whether be could have done or couldn't have done them.
1. Ken's aunt wanted him to drive her to the airport on Tuesday.
He couldn't have driven her to the airport (because his car had been stolen).
2. A friend of his wanted him to go out for a meal on Friday evening.
Ken ---
3. Another friend wanted him to play tennis on Monday afternoon.
Ken ---
4. Jack wanted Ken to lend him l50 last week. ---
5. Jane wanted Ken to come to her party on Saturday. evening.
He ---
6. Ken's mother wanted him to repair her washing machine. ---
27.1
2 We could have fish.
3 You could give her a book.
4 You could phone her now.
5 We could go (and see him) on Friday.
6 We could hang it in the kitchen.
27.2
2 could 3 can/could
4 could 5 could
6 can 7 can/could 8 could
27.3
2 could have gone
3 could apply
4 could have gone
5 could come
27.4
2 Ken couldn't have gone out (for a meal) on Friday evening (because he had to work).
3 Ken could have played tennis on Monday afternoon.
4 He couldn't have lent Jack L50 (because he was short of money). or He couldn't have lent him L50.
5 He could have come to Jane's party. or He could have gone to.
6 He couldn't have repaired her washing machine (because he doesn't know anything about machines).
