DO is used as follows:
1. DO is used when talking about work, jobs or tasks. Note, they do not produce any physical object.
Have you done your homework?
I have guests visiting tonight so I should start doing the housework now.
I wouldn't like to do that job.
2. DO is used when we refer to activities in general without being specific. In these cases, we normally use words like thing, something, nothing, anything, everything etc.
Hurry up! I've got things to do!
Don't just stand there – do something!
Is there anything I can do to help you?
3. We sometimes use DO to replace a verb when the meaning is clear or obvious. This is more common in informal spoken English:
Do I need to do my hair? (do = brush or comb)
Have you done the dishes yet? (done = washed)
I'll do the kitchen if you do the lawns (do = clean, do = mow)
* Remember Do can also be as an auxiliary verb (for making questions in the present tense