SUBJECT VERB AGREEMENT

Ex. My parents are both senior citizens.

All our online classes last for 30 minutes.

If the subject is a singular noun or he, she, or it, add -s or -es to most verbs. (NOTICE, this is the opposite of making nouns singular.)

If the subject is compound, a plural noun, or I, you, we, or they, DO NOT add -s or -es to the verb.

For the verb be, use am and is to agree with singular subjects and are to agree with plural subjects.

Some indefinite pronouns can be either singular or plural: all, any, most, none, some - singular when they refer to a portion or to a single noun / plural when they refer to a number of individual nouns.

Sometimes, the object of the preposition will signal whether the pronoun is singular or plural.

Ex: None of their music makes sense to me. (None-singular)

Ex: None of the lyrics make any sense. (None-plural)

Some indefinite pronouns are always PLURAL and take plural verbs: both, few, many, others, several. 

Ex: Many of my friends are serious readers. (Many-plural)

An indefinite pronoun does not refer to a specific person, place, or thing.

Some of these are always singular and take singular verbs: anybody, anyone, anything, each, either, everybody, everyone, everything, much, neither, nobody, no one, nothing, one, somebody, someone, something.

Ex: Nobody wants that jacket. (Nobody-singular / wants-singular)