Sentence agreement: indefinite pronouns
Indefinite pronouns can be singular or plural. They do not refer to any person or thing is particular but are used in a general way.
Singular indefinite pronouns (e.g. someone, anyone, everyone, one, somebody, anybody, everybody and nobody) take a singular verb; plural indefinite pronouns (e.g. both, few, many, others and several) take a plural verb. The indefinite pronouns all, any, more, most, none, and some can be singular or plural, depending on how they are used.
One of my friends is a journalist.
The singular subject one requires the singular verb is.
Nobody has arrived yet.
The singular subject nobody requires the singular verb has.
Both boys were given scholarships.
The plural subject both requires the plural verb were.
All cheese contains fat.
When the indefinite pronoun all is followed by an uncountable noun, the verb is usually singular.
All my friends like riding.
All the lights were out.
When the indefinite pronoun all is followed by a plural noun, the verb is usually plural.
None of his friends have come forward to help him.
None of these conditions is acceptable to us.
None means not one. It may be followed by a singular or plural verb.
Other examples are given below.
Some are lucky, others are not.
Many were killed in the accident.
All were involved in the accident.