1.2 Types of sentences

There are four basic types of sentences in the English language: declarative, interrogative, imperative, and exclamatory sentences.

A declarative states a fact or makes a declaration. The subject usually precedes the verb and it ends with a full stop period.

Interrogative sentences are used to ask questions. There's always a WH word (what, who, where, which) or a verb at the beginning of the sentence. In this case, the verb appears before the subject, and the sentence always ends with a question mark. 

Imperative sentences express a request or command. They are also used to give instructions or advice. It's a very simple sentence to form and use because it takes the verb's infinitive form. Usually the verb will be placed at the beginning of the sentence.

And last but not least, exclamatory sentences, which express strong emotion. They require appropriate intonation and the use of an exclamation point at the end.