Bài soạn môn Tiếng Anh 11 - Can / could vs. be able to

CAN/COULD vs. BE ABLE TO
A natural or learned ability:
I can (I am able to) run 1500 meters in 5 minutes. (natural ability)
I can’t (I am not able to / I am unable to) drive. (learned ability)
* can is more common in those cases.
* In the sense of “know how to”, or with verbs of perception like see, hear, taste, feel, smell, understand, remember, guess,  can is more preferable.
General ability in the past:
She could read when she was four.
She was able to read when she was four.
Successful completion of a specific action:
We were able to get tickets for the match yesterday.
A specific action which was not successfully completed:
We couldn’t get tickets for the match yesterday.
We were not able to get tickets for the match yesterday.
Be able to is used instead of can/could in these cases:
I would like to be able to afford a new car. (to infinitive)
Why don’t you ask her? She might be able to help. (bare infinitive)
I enjoy being able to take a swimming every morning. (gerund)
Unfortunately, he hasn’t been able to walk since his accident. (perfect)
When will you be able to repay me? (future)
PRATICE:
Complete the following sentences with can/could or be able to
A good 1500-runner ....................... run the race in under four minutes.
Bill is so unfit, he ....................... run at all!
Our baby is only nine months and he ...................... already stand up.
When I was younger, I ...................... speak Italian much better than I ....................... now.
....................... she speak German very well? – No, she ....................... speak German at all.
He ...................... draw or paint at all when he was a boy, but now he’s a famous artist.
After weeks of training, I ....................... swim a length of the baths underwater.
Ii took a long time, but in the end Tony ...................... save enough to buy his own hi-fi.
Did you buy any fresh fish in the market? – No, I ....................... get any.
For days the rescuers looked for the lost climbers in the snow. On the fourth day they saw them and ....................... reach them without too much trouble.
He was very strong, he ....................... ski all days and dance all night.
The car plunged into the river. The driver ....................... get out but the passenger was drowned.
I was a long way from the stage. I ...................... (negative) see all right but I ....................... hear very well.
We ....................... borrow umbrella, so we didn’t get wet.
....................... you walk or did they have to carry you?
I had no key so I ....................... (negative) lock the door.
I knew the town, so I ...................... advise him where to go.
When the garage had repaired our car we ...................... continue our journey.
At five years old, he ....................... read quite well.
When I arrived, everyone was asleep. Fortunately, I ....................... wake my sister and she let me in.
The swimmer was very tired but he ....................... reach the shore before he collapsed.
The police were suspicious at first but I ...................... convince them that we were innocent.