1. SUBJECT-VERB AGREEMENT

2. DOESN’T Singular nouns and pronouns use the contraction doesn’t
This piece doesn’t look like the one we need.
He doesn’t need to exercise that frequently.

3. DON’T Plural nouns and pronouns use the contraction don’t
These occasions don’t need to be photographed.
They don’t remember you saying that.

4. COLLECTIVE NOUNS
When it refers to a unit or as a whole, than use a singular verb and pronoun.
The squad is meeting this afternoon. Its president is Sarah.

5. COLLECTIVE NOUN
When a group is considered as individuals, the collective noun is plural.
The squad brought their notebooks.

6. LOOKS PLURAL?
Some nouns that look plural take singular verbs and pronouns
i.e. economics, gymnastics, mathematics, news, physics, social studies, and others.
Physics is a challenging subject for Mitch because it demands much time and intelligence.
Social studies is an interesting subject.

7. AMOUNTS
Fractions, measurements, percentages and time periods can be singular OR plural
Sixteen hours is a very long time to wait.
Five dollars was left on the table.
Five one-dollar bills were left on the table.
Two-thirds of the drummers are practicing.

8. TITLES
The title of a book, city, country, film, magazine, organization, painting, sculpture or song that is plural still takes a singular verb.
Des Moines is Iowa’s Capital City.
The Rolling Stones is my uncle’s favourite band.