Present tense

Do and does are used when we want to ask yes/no questions.

We use do or does depending on the subject. Below are two sentences with two different subjects,she and you.

Does she like movieYes, she does.

Do you like movie? Yes, I do.

Do

We use do when the subject is I, you, we or they.

Do I know you?
Do you come from Spain?
Do we have to cut the grass?
Do they want to come with us?

Does

We use does with third person singular pronouns i.e when the subject is he, she or it.

Does he work with you?
Does she have a dog?
Does it snow in winter?

Negatives

The negative form of do is do not. In spoken English it is common to use the contracted form of do not which is don't.

I do not like sport.
I don't like sport.

The negative form of does is does not. Also, in spoken English we usually use the contracted form of does not which is doesn't.

He does not like sport.
He does't like sport.

Past Tense

Did is the past form of both do and does.

Did he call you?
Did you enjoy it?

The negative form of did is did not or when speaking, didn't.

I did not know you were coming.
I didn't know you were coming.