Once upon a time I had to write a house style guide from scratch. Someday I'll do a post on the process of creating that guide, but in the meantime, I thought I would post some excerpts from it. Last week, in response to a bunch of questions about possessive nouns, we looked at the basic rules for apostrophes and apostrophe-s constructions. Today we'll look at compound nouns and the number of the verb. This is one of those little nitpicky things that can lead to big-time copy editor battles.
When a subject is a compound joined by the conjunction and, it takes a plural verb regardless of the number of each individual noun in the subject.
EXAMPLE: Lucy and Harry were childhood sweethearts.
When a subject is a compound composed of two singular nouns joined by or or nor, it takes a singular verb.
EXAMPLE: Either Lucy or Harry always orders apple pie.
When a subject is a compound composed of two plural nouns joined by or or nor, it takes a plural verb.
EXAMPLE: The Smiths or the Joneses want their pie heated.
Or/Nor With Singular and Plural
When a subject is a compound composed of a singular and a plural joined by or or nor, the verb agrees with the part of the subject closest to it.
EXAMPLE: Either Lucy or the Smiths are wrong.
EXAMPLE: Either the Smiths or Lucy is wrong.
Exception: When a compound noun is thought of as a single unit, it is treated as singular regardless of the number of the nouns contained therein. Therefore, “macaroni and cheese” (singular and singular), “peas and carrots” (plural and plural), and “chicken and dumplings” (singular and plural) each take singular verbs despite differences in the numbers of the nouns.
Also note: Odd singular-plural agreement constructions can be avoided by editing the structure of the sentence.
EXAMPLE: Either Lucy is wrong, or the Smiths are.