What is the difference between I play and I do play?
If someone were to ask to me, do you play soccer?
In modern English, auxiliary 'do' is used in five cases:
In older English, and some dialects, it may be used outside these cases, but not normally in modern standard dialects.
If someone asks
it would be unnatural though correct to reply
Usually one would reply with one of the following.
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
you would reply