The basic principle of subject-verb agreement is simple. If the subject is singular, it should be followed by a singular verb. If the subject is plural, it should be followed by a plural verb.
- My brother is an engineer. (Here the singular verb is agrees with the singular subject brother.)
- My brothers are engineers. (Here the plural verb are agrees with the plural subject brothers.)
Sometimes it is not easy to see whether a subject is singular or plural. Here are some general guidelines.
The indefinite pronouns anyone, everyone, someone, no one and nobody are always singular and take singular verbs.
Examples are given below.
- Everybody has brought his or her violin. (NOT Everybody have…)
- Nobody is interested in the project. (NOT Nobody are ….)
- Someone has let the cat in. (NOT Someone have …)
- Anyone who is interested in improving his or her English can join the club. (NOT Anyone who are…)
The pronoun referring back to a singular indefinite verb is usually singular. However, this can be a problem when the sex of the person is unknown. And hence plural pronouns are now used to refer to indefinite pronouns in a less formal style.
- Everybody has brought their violins.
- Anyone who is interested in improving their English can join the club.
Some indefinite pronouns can be plural or singular depending upon the context. Examples are: some and all. When they are used to modify uncountable nouns, they take the singular verb. When they are used to modify plural nouns, they take a plural verb.
- Some of the eggs are rotten.
- Some of the meat has gone stale.
The indefinite pronoun none can be either singular or plural – it doesn’t really matter whether it is followed by a singular verb or plural verb.