A sentence is a group of words that expresses a complete thought. The first word of a sentence begins with a capital letter. All sentences end with a punctuation mark. Declarative sentences make statements and end with periods. Interrogative sentences ask questions and end with question marks.
Imperative sentences make requests or give commands and end with periods.
Exclamatory sentences show excitement or strong feeling and end with exclamation points. There are two parts to a sentence, the subject and the predicate. The subject tells what or whom the sentence is about. The predicate tells what the subject does. The complete subject includes all the words in the subject.