When to use do?

[123Amigo]

Hello everbody,

I have a short and which I guess easy question for you, but I can't find any useful answers about that on the internet.

When do you use do?

For instance where is the difference between:
"It rained."
and
"It did rain."

Can you say both? Or when do you use do/does/did in front of a verb and when not?

Kind regards and thank you for the explanations.
123Amigo

[Barb_D]

You must use a form of "to do" to ask the question and to make it negative.

Did it rain? It didn't rain.

You may use a form of "to do" to make it emphatic, to express surprise or some other emotion. They said we'd have another week of this drought, but look, it DID rain!

To simply make a statement about the past, omit the "did." It rained.

[123Amigo]

Thank you for the good and quick explanation! :)

[Barb_D]

PS - Welcome to Using English.