what is a sentence?
expresses a complete thought, has a subject and a verb, has an object and/or other information
what is the subject?
is the person or thing that does the action, can be a noun or a pronoun
what is the verb?
shows the action or state of the subject, is sometimes an action word, such as "go", "speak", "write", ...., and is sometimes a non-action word, such as "be"