You can use the imperative form to give an order, to give a warning or advice, and (if you use "please") to make a request.
To make the imperative, use the infinitive of the verb without 'to':
"Come here!"
"Sit down!"
To make a negative imperative, put "do not" or "don't" before the verb:
"Don't go!"
"Do not walk on the grass."
The
imperative can be used for all subjects (you, he, they and we), but you
can also use "let's" before the verb if you are including yourself in
the imperative:
"Let's stop now."
"Let's have some lunch."
The negative of "let's" is "let's not":
"Let's not argue!
"Let's not tell her about it."
Orders
Adults
do not usually give each other orders, unless they are in a position of
authority. The intonation of an order is important: each word is
stressed, and the tone falls at the end of the sentence:
"Sit down now!" ('Sit', 'down' and 'now' are all stressed, and the tone falls on 'now'.)
However, adults can give orders to children and to animals:
Here are some orders you could give your pet dog:
"Come here!"
"Sit!"
"Heel!"
"Fetch!"
Warnings
You
can use the imperative to warn someone of danger. All the words in the
warning are stressed, but the last word has a higher tone than the first
word:
"Watch out!"
"Look out!"
"Don't cross!"
Advice
When you give advice using the imperative, the words are stressed normally:
"Eat an apple – it's much better for you than a biscuit!"
"Don't tell him you're resigning now! Wait until Monday when he's in a better mood."
You can often read articles in magazines that give advice on a subject. Sometimes, this advice is presented as "Dos and don'ts".
For example:
Travelling long-distance
Do try to sleep well the night before
Do drink plenty of water
Do try to walk about the plane during the flight
Don't drink alcohol
Don't eat heavy meals
Don't wear restrictive clothing
Requests
You can also use the imperative to make a request, but you should use a polite word before the verb:
"Please take a seat."
"Please wait here."
"Please hold the line."
"Please don't smoke here."
In written English, you might also see "Kindly" used as a polite word:
"Kindly return the documents as soon as possible."
"Kindly forward this to the Sales and Marketing department."
"Kindly send me 2 copies of your brochure."