(Plural and Singular)
Plural verb = I, you
Singular = He, she, it
(Auxiliary verb)
-> do/does 
-> am/is/are/was/were
-> have/has
Example:
- Rangga and Rizky have been swimming for hours.
- Rangga has been running 3km.
(Modal verb)
The verb following a modal verb is never in the "S" form. It's always in the infinitive form.
=>may, must, could, should, will.
(Indefinite Pronoun)
Usually indefinite pronoun take singular verb.
=>everybody, nobody, anybody, someone.
Example :
Nobody wants to be lonely.
(Compound Subjects)
Group nouns and relative clauses.
(Group Nouns)
Single nouns that are actually groups of people or things.
=>club, team, company, family, class, subject, singular verb.