1. A verb shows action or a state of being.
Ex : I go home.

2. "Be" verbs indicate a state of being. Verbs must match subjects.
Ex : I am a doctor.

3. Negative sentences need ‘not' after the verb.
Ex : I am not a doctor.

4. The verb comes first in interrogative sentences.
Ex : Am I a doctor?

5. "Are not" (is not) can be shortened to "aren't" (isn't).
Ex : He isn't sleepy.