Can, could, be able to test

1. Can be able or could be able?
2. Can we use could be able to?
3. When to use can or able to?
4. Is could used for ability?

Can be able or could be able?

Be able to is possible in all tenses - but "can" is possible only in the present and "could" is possible only in the past for ability. In addition, "can" and "could" have no infinitive form. So we use be able to when we want to use other tenses or the infinitive.

Can we use could be able to?

You use could or a past form of be able to to talk about ability in the past. He could run faster than anyone else. A lot of them couldn't read or write. I wasn't able to answer their questions.

When to use can or able to?

We use 'can' and 'be able to' to talk about abilities, knowledge, or talent. We use 'can' to talk about the present and the future. 'Be able to' is used in all tenses to show ability.

Is could used for ability?

We use could have to say that someone had the ability or opportunity to do something, but did not do it: She could have learned Swahili, but she didn't want to.