Subject Verb Agreement: Part 1

1. When the subject of a sentence is composed of two or more nouns or pronouns connected by and, use a plural verb.
Example: She and her friends are at the fair.
 
2. When two or more singular nouns or pronouns are connected by or or nor, use a singular verb.
Example: The book or the pen is in the drawer.
 
3. When a compound subject contains both a singular and a plural noun or pronoun joined by or or nor, the verb should agree with the part of the subject that is nearer the verb.
Example: 1. The boy or his friends run every day.
               2. His friends or the boy runs every day.
 
4. Doesn't is a contraction of does not and should be used only with a singular subject. Don't is a contraction of do not and should be used only with a plural subject. The exception to this rule appears in the case of the first person and second person pronouns I and you. With these pronouns, the contraction don't should be used.
Example: 1. He doesn't like it.
               2. They don't like it.