Это зависит от многих факторов. Вот несколько правил.
1. Use verbs that agree with a subject, not with a noun that is part of a modifying phrase or clause between verb and subject:
> “The pot of eggs is boiling on the stove.”
2. Use singular or plural verbs that agree with the subject, not with the complement of the subject:
> “My favorite type of movie is comedies,” but “Comedies are my favorite type of movie.”
3. Use singular verbs with singular indefinite pronouns — each, the “-bodies,” “-ones,” and “-things” (anybody, everyone, nothing), and the like:
> “Neither is correct.” (And, just as in rule number 1, the presence of a modifier is irrelevant: “Neither of them is correct.”)
4. Use plural verbs with plural indefinite pronouns:
> “Many outcomes are possible.”
5. Use singular verbs with uncountable nouns that follow an indefinite pronoun:
>“All the paint is dried up.”
6. Use plural verbs with countable nouns that follow an indefinite pronoun:
> “All the nails are spilled on the floor.”
7. Use plural verbs with compound subjects that include and:
> “The dog and the cat are outside.”
8. Use plural verbs or singular verbs, depending on the form of the noun nearest the verb, with compound subjects that include nor or or:
> “Either the dog or the cats are responsible for the mess.” (“Either the cats or the dog is responsible for the mess” is also technically correct but is awkward.)
9. Use singular verbs with inverted subjects that include singular nouns:
> “Why is my hat outside in the rain?”
10. Use plural verbs with inverted subjects (those beginning with the expletive there rather than the actual subject) that include plural nouns:
> “There are several hats outside in the rain.”
11. Use singular or plural verbs with collective nouns depending on meaning:
> “His staff is assembled,” but “Staff are asked to go to the conference room immediately.”
(In the first sentence, the emphasis is on the body of employees; in the second sentence, the focus is on compliance by each individual in the body of employees.)
12. Use singular verbs for designations of entities, such as nations or organizations, or compositions, such as books or films:
> “The United Nations is headquartered in New York.”
13. Use singular verbs for subjects plural in form but singular in meaning:
> “Physics is my favorite subject.”
14. Use singular or plural verbs for subjects plural in form but plural or singular in meaning depending on the context:
> “The economics of the situation are complicated,” but “Economics is a complicated topic.”
15. Use plural verbs for subjects plural in form and meaning:
> “The tweezers are in the cupboard.”
16. Use plural verbs in constructions of the form “one of those (blank) who . . .”:
> “I am one of those eccentrics who do not tweet.”
17. Use singular verbs in constructions of the form “the only one of those (blank) who . . .”:
> “I am the only one of my friends who does not tweet.”
18. Use singular verbs in constructions of the form “the number of (blank) . . .”:
> “The number of people here boggles the mind.”
19. Use plural verbs in constructions of the form “a number of (blank) . . .”:
> “A number of people here disagree.”
20. Use singular verbs in construction of the forms “every (blank) . . .” and “many a (blank) . . .”:
> “Every good boy does fine”; “Many a true word is spoken in jest.”
___________
(зд.)
singular - единственное число (2. особый)
plural - множественное число
uncountable - неисчисляемое
complement of ... - дополнение ...
indefinite - неопределенный
noun - существительное
pronoun - местоимение