It is the most common type. Declarative sentence makes a statement, expresses opinion. It usually ends with a period “.”
A declarative sentence may be positive (affirmative) or negative.
If it’s a regular positive sentence, it starts with the subject, then the predicate comes, and then the rest of the sentence.
She is reading a book in the library. (She – the subject, is reading – the predicate)
I am a doctor. (I – the subject, am a doctor – the predicate (compound nominal predicate))
We form the negative sentence by placing the negative particle “not” after the auxiliary, link or modal verb.
She is not reading a book in the library. (= She isn’t reading)
I am a doctor. (= I’m not a doctor))
We can’t abbreviate am and not, but in certain questions we can. Please refer to interrogative sentences. Quickly here:
I am a doctor, aren’t I
And the one with the modal verb:
She can not read a book in the library. (= She can’t read)
We can use declarative sentences in any tense and in any voice (active or passive).
He asks 5 questions a day. (active)
He is asked 5 questions a day. (passive)
They don’t make commands or requests, make emotional statements or express an opinion with emotion. They don’t ask questions. However, it’s not quite so. There are some situations when we use the form of declarative sentence to express commands, for example.
You will do what I say.
In this example a true imperative sentence would sound like:
Do what I say!
But by the form and construction this sentence is declarative, by the purpose or job – it’s imperative.
He is an example of an interrogative sentence in the form of the declarative sentence (subject – predicate). It is very common in spoken English.
You play Xbox?
A true interrogative sentence will sound like this:
Do you play Xbox?
Another example, this time with emotion. The sentence is in declarative form:
You are so beautiful!
A true exclamatory sentence will sound like:
How beautiful you are!
So it’s good to know that declarative sentences are universal, especially in spoken English. However, learning other types will significantly enrich your speech and help pass tests.