Students should know that when writing, the type of sentence they use at a given place must be tied to the purpose of the sentence.  Review these four types of sentences and the purpose of each with your students. 1.  Use a declarative sentence to make a statement or express an opinion.  End this type of sentence with a period. Algebra involves a different thinking   process than does geometry. 2.   Use an interrogative sentence to ask a question.  End this type of sentence with a question mark. Who was the inventor of the automobile? 3.  Use an exclamatory sentence  to express strong feeling.  End this type of sentence with an exclamation point. I absolutely hated that movie! 4a.  Use an imperative sentence to make a request.  End this type of sentence with a period. Please clean your room before you go out. 4b.  Use an imperative sentence to give a command.  End this type of sentence with an exclamation point. Do not go out until you have cleaned your room!