Question 1

What is the difference between can and could?

Accepted Answer

"Can" talks about the present — what you are able to do right now: "I can speak English" (I have this ability now). "Could" has two main uses. First, it talks about past ability — what you were able to do before: "I could run fast when I was young" (but maybe not now). Second, "could" is a polite way to ask for something: "Could you help me?" is softer than "Can you help me?" Both are correct, but "could" sounds more polite and formal. In exams, remember: "can" = present ability, "could" = past ability or polite request. For future ability, use "will be able to": "I will be able to drive next year."

Question 2

How do I make questions and negatives with can?

Accepted Answer

The negative of "can" is "can't" (or "cannot" in formal writing). Put "can't" before the base verb: "I can't swim," "She can't come today." For questions, put "can" before the subject: "Can you swim?" "Can she come?" There is no "do" or "does" — we never say "Do you can swim?" This is a common mistake. Short answers use "can" or "can't": "Can you drive?" — "Yes, I can" or "No, I can't." In writing, "cannot" is one word (not "can not"), and "can't" is the short form used in speech and informal writing.

Question 3

Can I use "can" to ask for permission?

Accepted Answer

Yes, "can" is commonly used to ask for and give permission in everyday English: "Can I borrow your pen?" "You can go now." However, "can" is informal — in more polite or formal situations, use "could" or "may": "Could I borrow your pen?" or "May I borrow your pen?" In traditional grammar, "may" is considered the correct word for permission, and some teachers still prefer it. In modern everyday English, most native speakers use "can" for permission without any problem. For Cambridge and IELTS exams, know that "may" is formal permission and "can" is informal permission.

Can and Can't Exercises

Quick Rule

Continue Practising

Modal Perfects Error Correction

Modal Verbs Error Correction

Must / Have to

-ed vs -ing Adjectives

Conditionals

Present Perfect