Using “can”, “could”, “be able to”
Expressing ability & possibility. Using “can”, “could”, “be able to”
Bill Gates (Chairman of Microsoft Corporation) is the richest man on Earth. When he was eight years old.
He was able to read "the book Encyclopedia" (a quite large book). He is hoping that one day everybody will be able to have a personal computer in his pocket. Nobody will disagree with you if you say that Bill Gates can buy almost anything he wants.
Can = am / is / are able to…: express ability in the present.
- Bill Gates can buy almost anything he wants. He is the richest man in the world, so he is able to buy all he wants.
- He was able = he was capable
- Could = was / were able to…..express ability in the past
At the age of 8 Bill Gates could read the book Encyclopedia.
Will be able to: express ability in the future.
Every body will be able to have a personal computer.
To express inability we add “not”
- Cannot = can’t / could not = couldn’t / was able to = wasn’t able to.
- Were able to = weren’t able to /will not able to = won’t able to.
tenses |
ability | inability |
Present ability |
Can + verb(bf) Am/is/are able to +verb(bf) Exemple: I can speak English well. I am able to speak English well. |
Cannot = can’t + verb(bf) am/is/are not able to = verb(bf) Exemple: I can’t speak Chinese. I am not able to speak Chinese. |
Past ability |
Could + verb(bf) Was/were able to + v(bf) Exemple: I could read when I was 5 years. |
could not = couldn’t + verb(bf) Was/were not = weren’t + verb(bf) I couldn’t swim when I was a baby. I wasn’t able to swim when I was a baby. |
Future ability |
Will be able to + verb (bf) Exemple: I will be able to speak English fluently in 2 months. |
Will not = won’t be able to + verb(bf) Exemple: I won’t be able to finish my project. |
- Can a baby walk at the age of 2 months? Why?
- No, He can’t because he is too young to walk. It’s impossible.
- Can elephant fly?
- No, it can’t fly because it doesn’t have wings.
- Can people swim in winter?
- No, they can’t swim in winter because it’s too cold.
Can: express possibility.
Can’t: express impossibility.
To express possibility, we use the modals: “can” “could” ”may” + verb infinitive.
Use of “could” is less sure.
”May” can be used to express the future.
we use possibility when there is a chance that something may happen.