Modals of ability and permission

Can, could, be able to, be allowed to:

We use the modal verb can to talk about ability in the present.

• My boyfriend can ride a motorbike.

We use the modal verb could to talk about ability in the past.

• I couldn't drive last week, but I can now!

As can and could cannot be used to talk about ability in all tenses, we use be able to (which is not a modal verb) in other tenses.

• Soon Peter will be able to speak Spanish fluenty.

We use the modal verb can to talk about permission in the present.

• Can we go?

As can cannot be use in all tenses, we use be allowed to (which is not a modal verb) to talk about permission in other tenses.

• I won't be allowed to go to the Coldplay concert next weekend.

We can also use could to talk about general permission in the past. However, we cannot use could to talk about permission for a particular action in the past. Instead, we use the correct form of be allowed to.

• When I was litte, I could watch cartoons whenever I wanted to. (general permission)
• Yesterday evening. I was allowed to watch a cartoon. (permission for a particular action in the past)