3. We use Can when we have the ability,
time or will to do something. For
example: I can play the guitar. OR I can
go to the store later (I have the time
to go soon). We use Cannot (or Can't) when we
don't have the ability, the time or the
will to do something. For example: I
cannot sing. (I do not have the ability
or the skill).
Can/Cannot in affirmative and negative sentences.
The verb To Be is NOT conjugated. It is simply be. This is because after Can and
Can't we use the infinitive of the verb.
Also, the word Can and Can't do NOT change because of He, She or It. It is simply
Can or Can't.
He cans go. --> This is incorrect.
He can goes. --> This is incorrect.
He cans goes. --> This is incorrect.
He can go. --> This is correct.
A common mistake for students is to put the word to between
can and the verb. This is incorrect.
I can to travel on Monday. --> This is incorrect.
I can travel on Tuesday. --> This is correct.