What is the difference in meaning between "I play" and "I do play"? [closed]
In modern English, auxiliary 'do' is used in five cases:
Negative (obligatory for most verbs): "I don't like mushrooms".
Interrogative (obligatory for most verbs): "Do you like mushrooms?"
Emphatic: "Oh, you've done some cauliflower! I do like cauliflower!"
Contrastive (a special case of emphatic). "I don't like mushrooms. But I do like cauliflower".
Anaphoric for the main verb: "Do you like cauliflower?" "Yes, I do".
In older English, and some dialects, it may be used outside these cases, but not normally in modern standard dialects.
If someone asks
Do you play soccer?
it would be unnatural though correct to reply
I play soccer.
Usually one would reply with one of the following.
Yes, I do.
No, I don't.
There is a situation in which one would use do followed by a verb, and that is for reasons of emphasis. For instance, if your girlfriend asks you
Do you care about me at all?
you would reply
I do care.