Declarative sentences tell information and end in a period.
example: Mom and Dad said that we are getting a new puppy soon.
Imperative sentences also end with periods, but give commands or requests, instead of telling information. Even though the word "you" may not appear in the sentence, it is always the understood subject.
example: Wash the puppy's food and water bowls.
(Note: The author is telling you to wash the puppy's food and water bowls, but did not have to include the word at the beginning of the sentence because you understood who the author was talking to.)
Exclamatory sentences end with an exclamation mark and show strong feelings (usually excitement, anger, or surprise).
example: I can't wait to get my new puppy on Saturday!
Interrogative sentences end with a question mark and ask questions. (Think of a cop interrogating a bad guy for information to help you remember this one).
example: Why can't our puppy come live with us before Saturday?
Interjections are words or groups of words that show strong feeling and end with an exclamation mark but are not sentences.
examples: Wow! Hooray! Ouch! Yippee!
