And, Both, As well as—When we join things, are they always plural?

Which of the following is incorrect?

1. Both the status report on the bridge project, as well as the budget report, are in the folder.

2. The page proof as well as the list of corrections has been sent.

3. Smith, Michaels and Jones is our law firm.

I often see errors of verb agreement in business writing, even though at its most basic level, verb agreement is considered quite elementary. After all, almost no-one who writes professionally would say “the reports is in the folder” or “the project are complete.”

How, then, do we end up with verb agreement problems in professional writing? Often the problems occur when more than one subject precedes the verb in a sentence.

The basic rule for multiple subjects is that when two or more subjects are connected by the word “and,” a plural verb is used. For example, “My dog and my cat [a total of two pets] are [plural verb] hiding behind the couch.”

The second rule, however, is that if you use a connecting phrase other than the exact word “and,” the subjects do not add up. So when you connect two subjects with phrases such as “as well as,” “in addition to,” “along with,” the additional subjects do not count. For example, “My dog [the main pet I am discussing] as well as my cat [which does not count, because I used a phrase other than “and”] has [singular verb] fleas.”

Another problem that comes up with “and” versus other connecting phrases is the use of the word “both” in front of any other connector but “and.” The words “both” and “and” form a team, known as a correlative conjunction, and “both” cannot be used with other phrases. “Both Jack as well as Jill” is completely wrong. Either eliminate “both” or use “and” instead of “as well as.”

Finally, there is an exception to the “and makes plural” rule. I call it the macaroni and cheese rule. Some phrases containing the word “and” actually describe a singular thing, like macaroni and cheese. When you eat macaroni and cheese for dinner, you are eating one dish. The macaroni and the cheese are all mixed together to form one substance. So we correctly say “The macaroni and cheese [one substance] is [singular verb] good tonight.”

Not only other foods, such as spaghetti and meatballs, but also many proper nouns and job titles contain the word “and” but name a singular thing:

Steak and eggs is my favorite breakfast.

The Stars and Stripes is waving atop the flagpole.

Smith and Jones is the accounting firm.

Our secretary and treasurer is Mike.

With these rules and exceptions duly noted, by now you can be sure: No. 1 is incorrect, and Nos. 2 and 3 are correct.