Past Simple, used to

You buy this car?

You bought this car?

Did you buy this car?

Bought you this car?

I wrote the letter not

I didn’t write the letter.

I write didn't the letter

Did you use to spend a lot of time in crowded places?

Did you spend a lot of time in crowded places?

You used to spend a lot of time in crowded places?

We didn't use talk with our neighbours in apartment.

We didn't talk with our neighbours in apartment.

We used to talk with our neighbours in apartment.

We didn't use to talk with our neighbours in apartment.