The Editor's Manual
Free learning resource on English grammar, punctuation, usage, and style.
“One in” followed by a number (e.g., “one in five”) is grammatically singular. However, such phrases refer not to one person or thing but to a proportion, and the use of plural verbs is acceptable, although singular verbs are preferred in formal usage.
Use “each of” with singular verbs to refer to every one of a group separately. “Each of” may be followed by a plural, gender-neutral pronoun. In spoken English, “each of” is sometimes used with plural verbs to refer to an entire group.
When “each” is part of the subject of a sentence, it is used with singular verbs, except when it follows a plural noun. “Each” may be used with a plural pronoun in an indefinite reference.
Names of decades and centuries (the 1800s, the 1970s, the eighties, the ’90s) are generally considered plural but can also be used with singular verbs.
Use the correct form of the verb with singular and plural subjects. To ensure subject-verb agreement, identify the subject and check whether it is singular or plural. Some subjects may appear plural but be singular.
“Any” can be singular or plural, depending on whether you mean “at least one” or “one or more.” It is generally used with uncountable and plural countable nouns in questions and negative statements, though it may be used with a singular countable noun for emphasis.
One of a group is singular (“one of them is” not “are”). But when “one of” is followed by “who” or “that,” check what is being described: one person or thing, or the plural set.
Use “either-or” to affirm the one or the other of two alternatives and “neither-nor” to negate them both simultaneously. Make sure that the elements joined using “or” and “nor” are grammatically balanced and parallel in structure.
“Either” is grammatically singular and used with singular verbs (like “is” and “has”) in formal usage. In informal usage, the word may be treated as either singular or plural.
“Neither,” which means “not either,” negates each of two possibilities individually. In formal writing, treat it as singular (“neither is”). In informal usage, it may take either a singular or a plural verb (“neither is/are”).