Use can for ability, possibility and permission, (be) able to wherever can has no form to offer, and could or was able to for the past, depending on whether you mean a general ability or one particular success.
A can: possible, allowed, able
We use can to say that something is possible or allowed, or that somebody has the ability to do something. The form is can + infinitive (can do, can hear, can be).
The negative is can't (= cannot). The written full form is one word, which is a small mercy.
- You can see the castle from our kitchen window.
- "I've left my umbrella at home." "You can borrow mine."
- Can you play any instruments?
- I can give you a lift to the station if you like.
- The word 'round' can be a noun, a verb or an adjective.
- I'm sorry, I can't come to the quiz on Thursday.
B (be) able to: where can runs out of forms
You can say that somebody is able to do something, but can is more usual in the present.
Can has only two forms: can (present) and could (past). It has no infinitive, no -ing form and no participle. After will, might, must, should, used to and the present perfect, therefore, you need (be) able to.
| can | (be) able to |
|---|---|
| I can't concentrate. | I haven't been able to concentrate all week. |
| Nadia can help us tomorrow. | Nadia might be able to help us tomorrow. |
| Ollie can drive a lorry. | Drivers for this job must be able to drive a lorry. |
- We're able to park right outside the house.
- I haven't been able to get hold of the landlord since Monday.
- You'll be able to see the fireworks from the bridge.
- I'd love to be able to speak Welsh.
C could as the past of can
Sometimes could is the past of can. We use it especially with these verbs:
see, hear, smell, taste, feel, remember, understand
We also use could to say that somebody had a general ability in the past, or was allowed to do something.
- Our cottage was on the cliff. We could hear the sea all night.
- The moment I opened the fridge, I could smell the fish.
- I was in the back row and couldn't see the stage properly.
- My great-aunt could recite every poem she learned at school.
- At my old job we could wear what we liked. (= we were allowed to)
D could or was able to?
Use could for a general ability, and with see, hear and the other verbs in C.
To say that somebody succeeded in doing something in one particular situation, use was/were able to or managed to, not could.
| General ability (could) | One specific success (was able to / managed to) |
|---|---|
| Kieran was a superb darts player. He could beat anybody in the pub. | Kieran and Steve played on Friday. Steve played well, but Kieran managed to beat him. |
The negative couldn't is possible in every situation, general or specific.
- The flood came up fast, but everyone was able to get out. (not could get out)
- I'd lost the address, but I managed to find the house in the end. (not could find)
- My grandad couldn't ride a bike.
- I rang the surgery all morning, but I couldn't get through.
- Steve played well, but he couldn't beat Kieran.
Exercises
26.1 Complete the sentences using can or (be) able to. Where can is not possible, use (be) able to.
Priya grew up in Montreal. She can speak French and English.
Priya grew up in Montreal. She can speak French and English.
My back has been bad. I haven't been able to sit down comfortably all week.
My back has been bad. I haven't been able to sit down comfortably all week.
Dev swim, but he hates getting his hair wet.
Dev can swim, but he hates getting his hair wet.
I used to touch my toes, but I can't do it any more.
I used to be able to touch my toes, but I can't do it any more.
Gran's handwriting is a mystery to me. I've never read it.
Gran's handwriting is a mystery to me. I've never been able to read it.
I can't make it on Tuesday, but I come on Wednesday.
I can't make it on Tuesday, but I can come on Wednesday.
Take the car to Mr Okafor at the garage. He might fix it.
Take the car to Mr Okafor at the garage. He might be able to fix it.
Be careful up on the moors in winter. The weather change very quickly.
Be careful up on the moors in winter. The weather can change very quickly.
Cerys has lived in Bilbao for ten years, so she should speak Spanish.
Cerys has lived in Bilbao for ten years, so she should be able to speak Spanish.
26.2 Write sentences about yourself, using the ideas in brackets.
(something you used to be able to do) I used ...
Example answer: I used to be able to do the splits.
(something you used to be able to do) I used ...
Example answer: I used to be able to run five miles without stopping.
(something you would like to be able to do) I'd ...
Example answer: I'd like to be able to play the piano.
(something you have never been able to do) I've ...
Example answer: I've never been able to whistle.
26.3 Complete the sentences with can, can't, could or couldn't and one of these verbs.
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My sister's getting married that day, so I'm afraid I can't come to your barbecue.
My sister's getting married that day, so I'm afraid I can't come to your barbecue.
At school, my dad faster than anyone else in his year.
At school, my dad could run faster than anyone else in his year.
"Shall I come back later?" "No, it's fine. I . I'm in no rush."
"Shall I come back later?" "No, it's fine. I can wait. I'm in no rush."
I'm shattered this morning. The neighbours' dog barked all night and I .
I'm shattered this morning. The neighbours' dog barked all night and I couldn't sleep.
Could you turn the radio up a bit? I it from over here.
Could you turn the radio up a bit? I can't hear it from over here.
When they told me I'd won the raffle, I it.
When they told me I'd won the raffle, I couldn't believe it.
26.4 Complete the answers to the questions with was/were able to ...
A: Did everybody get off the train? B: Yes. It stopped just outside the station, and everybody was able to get off.
Did everybody get off the train? Yes. It stopped just outside the station, and everybody was able to get off.
A: Did you finish the report last night? B: Yes. The house was quiet, so I .
Did you finish the report last night? Yes. The house was quiet, so I was able to finish it.
A: Did you fix the boiler? B: Yes, we did. It took us three hours, but we .
Did you fix the boiler? Yes, we did. It took us three hours, but we were able to fix it.
A: Did the dog get out of the garden? B: Yes. Somebody left the gate open and the dog .
Did the dog get out of the garden? Yes. Somebody left the gate open and the dog was able to get out.
26.5 Complete the sentences using could, couldn't or managed to.
Auntie Val was very musical. She could play the violin and the cello.
Auntie Val was very musical. She could play the violin and the cello.
I searched the whole house for my keys, but I couldn't find them.
I searched the whole house for my keys, but I couldn't find them.
The kids didn't want to go for a walk, but we managed to get them out of the house in the end.
The kids didn't want to go for a walk, but we managed to get them out of the house in the end.
Owen had sprained his ankle and climb the stairs.
Owen had sprained his ankle and couldn't climb the stairs.
The chip pan caught fire, but luckily I put it out before it spread.
The chip pan caught fire, but luckily I managed to put it out before it spread.
The people upstairs had wooden floors, and we hear every step they took.
The people upstairs had wooden floors, and we could hear every step they took.
The climb up Snowdon was exhausting, but we reach the top.
The climb up Snowdon was exhausting, but we managed to reach the top.
My uncle was a gifted artist. He draw anything you asked him to.
My uncle was a gifted artist. He could draw anything you asked him to.
We wanted to see the play, but we find a babysitter.
We wanted to see the play, but we couldn't find a babysitter.
A sheep got stuck in a ditch, but two walkers lift it out. It's absolutely fine now.
A sheep got stuck in a ditch, but two walkers managed to lift it out. It's absolutely fine now.