subject verb agreement situations

Here are some important rules and situations regarding subject verb

➲ Singular nouns and pronouns use the contraction doesn’t while plural
nouns and pronouns use the contraction don’t.

This piece doesn’t look like the one we need. (singular noun subject)
He doesn’t need to exercise that frequently. (singular pronoun subject)
These occasions don’t need to be photographed. (plural noun subject)
They don’t remember your saying that. (plural pronoun subject)
Note: Avoid using contractions in formal writing. Contractions are
allowable in dialogue.

➲ A collective noun (a name that refers to a group of people, animals,
or things, though they are singular in form) can be used as a
singular or plural noun.

➲ If the collective noun refers to a unit or as a whole, use a singular verb
and pronoun.

The squad is meeting this afternoon. Its president is Kanisha. (Squad is
considered a unit since all of its members will be meeting as a unit.
Thus, Its [not Their] is an appropriate pronoun reference.)

➲ When a group is considered as individuals, the collective noun is plural.
The squad brought their notebooks. (Squad refers to individual members
so the pronoun their is warranted.)

➲ Some nouns that look as if they are plural take singular verbs and
pronouns. These nouns include civics, economics, genetics, gymnastics,
mathematics, news, physics, social studies, and others.

Physics is a challenging subject for Mitch because it demands much
time and intelligence. (It is a pronoun reference to physics.)
Social studies is an interesting subject.