Subject to error

Knowing what form of a verb to mate with a subject isn't always simple. In a straightforward construction like, "The books are on the shelf" it's uncomplicated. Our subject, "books" is obviously plural, so we'd want to use the plural verb "are."

But what about this one: "The CEO, along with several other executives, is/are traveling today." If you said "are," you're wrong. But don't sulk. It's a common mistake. The error lies in thinking you have a multi-part, or compound, subject consisting of the CEO and the other executives. But actually, the subject is limited to the CEO, which is singular and takes the singular verb "is."

The rule to remember is that phrases such as "along with" and "in addition to" are used to shoehorn additional information into a sentence. They're not part of the subject, though, so don't let them fool you into choosing a plural verb when you want its singular cousin.

Another trap lurks when you have subjects that define units like money, measurement and diseases. These subjects take a singular verb, as in:

-- Three million dollars is all he was willing to pay.

-- Four thousand feet of road has been laid.

-- Mumps is a disease that threatens many children.

Avoiding subject-verb agreement errors not only requires knowing the special rules that apply, but being able to strip a sentence down to its main subject and main verb, which makes solving the puzzle easier. Good luck.