A verb that expresses a command or request is said to be an imperative, or to be in the imperative mood.
- Stop that right now!
- Give me a kiss.
- Answer the phone for me, please.
- Come in.
- Tell me all about your trip.
- Behave yourself!
- Please help me.
- Be sensible!
- Stay alert!
- Look happy!
Moods in grammar are different forms of a verb that express, for example, whether the action of the verb is a statement or a command, or a fact, a wish or a possibility.
Only finite verbs have different moods. That is another feature that distinguishes finite verbs from non-finite verbs.
Polite, persuasive or slightly annoyed requests use the auxiliary verb do along with a lexical verb:
- Do sit down.
- Do come in.
- Do have another cake.
- Do be quiet. I’m tired of listening to you.
Negative commands and requests formed with not and -n’t require the use of the auxiliary verb do along with a lexical verb.
Not and -n’t follow the auxiliary verb and precede the lexical verb.
- Please do not ask me for more money. You know I will say no.
- Do not be afraid.
- Don’t be silly!
- Don’t sit there. Come and sit over here.
- Please don’t worry about it. I can manage OK without you.
With never, there is no need for the auxiliary verb do:
- Never say that again!
- Never tell lies.
Normally, commands have no expressed subject (although the implied subject is always you). However, the subject pronoun you is sometimes used, especially for emphasis or when distinguishing between two or more people:
- You two boys come with me to the principal immediately.
- Don’t you ever do that again!
- You make the sandwiches, Mary, and Tim, you make the coffee.
One way of making suggestions in English is with let’s or, less commonly and in more formal language, let us, followed by the base form of a lexical verb.
- Let’s go to the pictures this evening.
- Let’s look in the paper and see what’s on TV tonight.
- Let’s talk about computers.
- Let us pray that it will not rain tomorrow.
If you want to be slightly more persuasive, you can say do let’s or do let us:
- Oh, do let’s buy that sweet little puppy.
- Do let’s have a party for all our friends.
Negative sentences with let’s and let us are formed with not, never with -n’t:
- Let’s not go to their party.
- Let’s not tell him what we’re going to do.
- Let’s not fight about it.
- Let us not worry about that until next week.
In informal British English, you can also say don’t let’s:
- Don’t let’s argue about money.
- Well, don’t let’s forget who’s paying for all this, then.
- Don’t let’s talk about computers for the whole evening.