There are four basic types of main clause: declaratives (statements), interrogatives (questions), imperatives (orders/instructions) and exclamatives (used for exclamations).
In the examples below, x is any other element in the clause (e.g. object, predicative complement):
Declarative clauses most commonly function as statements. The usual word order is subject (s) + verb (v) + x. Declaratives can be affirmative or negative. They make statements about how things are and how they are not.
Sometimes we use declaratives as questions or requests:
Those are the only tickets left? (question)B:
Yes, just those two.
You could pass me the spoon. That would be helpful. (request)B:
Interrogative clauses most commonly function as questions. The usual word order is (wh-word) + auxiliary/modal verb (aux/m) + subject + verb + x:
What [AUX] [S]are you [V]doing?
[AUX]Does [S]she [V]play [X]tennis well?
[M]Can [S] [V]I come [X]with you?
Interrogative clauses can be affirmative or negative.
Imperative clauses most commonly function as commands, instructions or orders. The usual word order is verb + x. We do not usually include the subject in an imperative clause. We use the base form of the verb:
Come on. Hurry up!
Leave me alone!
Put it in the microwave for two minutes.
Imperative clauses can be affirmative or negative. We make negative imperatives with auxiliary verb do + not. The contracted form don’t is very common in speaking:
We use do not in more formal contexts:
[instructions on a jar of coffee]
Do not make coffee with boiling water.
We can use the short form don’t as an imperative answer, or as a reaction to something:
Shall I open the window?B:
No, don’t. I’m freezing. (No, don’t open the window.)
Imperatives with subject pronoun
Sometimes we use you (subject pronoun) with an imperative clause to make a command stronger or to strengthen a contrast. It can sometimes sound impolite:
Don’t you ever read my letters again.
[talking about washing up dishes]
You wash, I’ll dry.
In informal speaking, we can use an indefinite subject (e.g. someone, somebody, no one, nobody, everyone, everybody) with an imperative:
No one move. Everyone stay still.
We often use an imperative to make an offer or invitation:
Have some more cake. There’s plenty there.
Imperatives with do
We sometimes use do for emphasis in an imperative clause, especially if we want to be very polite:
Do sit down, please.
Imperatives with let
In speaking we usually use let’s for first person plural imperatives (us) to make a suggestion. In more formal situations we use let us:
Let’s go and eat.
Now, let us all get some sleep. (more formal)
For third person imperatives (him, her, it, them) we form an imperative clause with let:
Mr Thomas is here to see you. Shall I send him in?B:
Let him wait. I’m busy.
Exclamative clauses usually have one of the following word orders:
What + noun + subject + verb
How + adjective or adverb + subject + verb
Auxiliary or modal verb + subject + verb (i.e. interrogative word order)
We use exclamative clauses most commonly to express surprise or shock. In writing we use an exclamation mark:
What a lovely sister you are!
How beautiful that house was!
Wasn’t she great!
Didn’t he sing well!