Is "I did buy a car yesterday" correct?

Question

Is that correct or I should say "I bought a car yesterday"? I mean, can I use

'do' as an auxiliary verb before the main verb in positive sentences?

Answer 1

Both are correct.

But they will be used in different scenarios.

1. I did buy a car yesterday.

   • This is used when you want to emphasise the action you performed(you buying a car is the action here).

If someone asks you - Hey, Did you buy a car?

This statement should be your answer.

Yes. I did buy a car yesterday.

2. I bought a car.

   • In the above sentence, you are just passing the information about the action you performed(may be to your friends or family).

Answer 2

If you are just making a statment of fact, then say

I bought a car yesterday.

You would use the do case when emphatically disagreeing with something someone else said to the contrary

P1: "You didn't do anything significant yesterday!" P2: "Well, I did buy a car, so that's something."

Verbal emphasis would be on the word "did."