Imperatives have exactly the same form as the infinitive without to. We use them, for example, for telling people what to do, making suggestions, giving advice, giving instructions, encouraging people, and offering things.
- Look in the mirror before you drive off.
Tell him you’re not free this evening.
Try again — you nearly did it!
Have some more tea.
Negative imperatives are made with don’t or do not.
- Don’t worry— everything will be all right.
Do not lean out of the window.
We can make an emphatic imperative with do. This is common in polite requests, complaints and apologies.
- Do sit down. Do try to make less noise.
Do forgive me — I didn’t mean to interrupt.
- Mary come here — everybody else stay where you are.
Somebody answer the phone!
- Come and help me, will you?
Give me a cigarette, could you?
Be quiet, can’t you?