Today, I have a short comment on subject-verb agreement when it comes to quantities.

I offer some examples of correct usage:

“Twelve years is a long time.”  Here, we are talking about a length of time as a collective unit.  We are actually saying “Twelve years is a long period of time.”  We use the singular verb.

But:  “Forty years pass in the blink of an eye.”  Here, we are speaking of more than one individual units, years.  Hence, we use the plural verb.

Similarly, “Three bottles of Southern Comfort is enough for the party.”

But, “Three cans of Dr. Pepper are missing.”

And, “Five copies of Crime and Punishment is plenty for the new library.”

But, “Six copies of To the Lighthouse are being shipped today.”