Q: I’m puzzling (or jousting) with another copy editor over which, if any, of these sentences should take a singular verb: (1) The bride, and the groom, look lovely. (2) The bride – and the groom – look lovely. (3) The bride (and the groom) look lovely. (4) The bride, as well as the groom, look lovely. (5) The bride, along with the groom, look lovely. Would you care to weigh in?
A: In general, two singular and separable nouns joined by “and” take a plural verb. (Sometimes, though, the two nouns refer to the same person and so are inseparable, as in “Our cook and housekeeper has resigned.”)
I find nothing indicating that the commas in sentence No. 1 would change this rule, though I find them awkward and unnecessary.
As for 2 and 3, parentheses and sets of dashes are functionally alike in that they isolate information that’s grammatically extraneous to a sentence. By this reasoning, the two sentences ought to take singular verbs, at least in theory.
But in fact, these sentences are constructed incorrectly, whether the verb is singular or plural. That’s because an extraneous element should not be included within the part of the subject that determines the form of a verb.
The Cambridge Grammar of the English Language (page 1750) gives this as an example of such an “inadmissible” sentence: “Kim (and Pat) have still not been informed.” Sentences 2 and 3 fall into this category and should be recast.
As for numbers 4 and 5, phrases like “as well as,” “accompanied by,” “added to,” “in addition to,” “along with,” “coupled with,” or “together with,” when inserted between subject and verb, don’t change the number of the verb. So if mere adjunct phrases like these follow a singular noun, the verb remains singular.
To sum up, I’d use a plural verb (“look”) with numbers 1, 2, and 3, after eliminating the commas from 1, the dashes from 2, and the parentheses from 3. I’d use a singular verb (“looks”) with 4 and 5.