Welcome to your CAN / COULD / BE ABLE TO lesson! In this topic we talk about:
• CAN.
• COULD.
Take the quizzes when you’re ready! If you’re having problems, use the comment box to contact our English Teachers.
CAN
CAN is used to say that something is allowed, or possible. It’s also used to talk about someone’s ability to do something.
You can park here, it’s free.
(Allowed)We can see the lake from our hotel window.
(Possible)Can you play the guitar?
(Ability)
The negative version of CAN is CAN’T or CANNOT:
You cannot be serious!
We can’t come tomorrow, sorry.
TO BE ABLE TO
TO BE ABLE TO is used to replace CAN when CAN is not possible. In situations where CAN is possible, CAN sounds more natural.
Can you play the guitar? sounds more natural than Are you able to play the guitar?
You can park here, it’s free. sounds more natural than You are able to park here, it’s free.
So when isn’t CAN possible? CAN only has two forms: CAN and COULD. So you can only use it in its present or past forms. In perfect sentences, or with other modal verbs like SHOULD or MIGHT, you have to use TO BE ABLE TO:
I haven’t been able to work recently.
I might be able to come to the picnic.
COULD
COULD is used to say that someone had an ability in the past, or was allowed to do something:
My grandfather could speak seven languages.
(Ability in the past)I could stay out until 11pm when I was 16.
(Allowed in the past)
COULD & WAS ABLE TO
COULD is used to express a general ability. When you want to say that a subject could do something in a specific situation, use WAS ABLE TO. You can also use MANAGED TO.
Smoke filled the flat, luckily everyone was able to escape.
Smoke filled the flat, luckily everyone managed to escape.
(This is a specific situation, so you can’t say:“Smoke filled the flat, luckily everyone could escape.”)
With negative sentences, COULDN’T or COULD NOT are possible in all situations, wether they are specific situations or not:
He couldn’t cook before he came to France.
I tried really hard, but I could not get the dinner to taste nice!
Recap
- CAN: Possibility, permission, ability in the present.
- CAN’T or CANNOT: The negative version of CAN.
- BE ABLE TO: Possibility, permission, ability in perfect sentences or with other modal verbs.
- COULD: General ability, permission in the past.
- WAS ABLE TO: Ability in a specific situation. Can be replaced with MANAGED TO.
- COULDN’T or COULD NOT: Ability or permission in the past. General or specific.
