According to the purpose of the utterance we usually distinguish four kinds of sentences:
The declarative sentences state a fact in the affirmative or negative form. In a declarative sentence the subject precedes the predicate. It is generally pronounced with the falling tone, e.g. Charles Dickens was born at Landport, Portsmouth.
The interrogative sentence asks a question. It is formed by means of inversion, by placing the predicate (or part of it) before the subject. There are four kinds of questions: