A sentence is a group of words that express a meaningful idea or an event. Basically words make up phrases; phrases make up clauses that in turn are called sentences. English sentences follow specific rules for construction, expansion or for making them short. A sentence normally begins with a capital letter and ends with any of the following punctuation mark: period, question mark or exclamation point. Variety in sentence structure is an important requisite for a good style. Subject and predicate form the core elements in an English sentence. It can further be classified into different sentence types like a declarative sentence, imperative sentence, a question and an exclamatory sentence. Furthermore, English sentences are classified into simple sentences (with one independent clause, compound sentences (with two or more independent clauses) complex sentences (with one independent clause and one or more dependent clauses) and compound complex sentences (with one or more independent clauses and one or more dependent clauses). In addition, English sentences are constructed around five basic patterns: S+V (subject +verb), S+V+O (subject+verb+object), S+V+Adj (subject+verb+adjective), S+V+ Adv. (subject+verb+adverb) and S+V+N (subject+verb+ noun). We have discussed only a preview of sentence structure and each element needs to be explained with details.