SAT question - neither...nor: singular/plural

spaceship42
Tue, 17 Jan 2012 18:13:08 +0000

I stumbled upon the following sentence correction question in the SparkNotes SAT prep corner:

“After Einstein, neither time-intervals or space-intervals (i.e., distances) is absolute; time and distance depend upon one’s frame of reference.”

Obviously, it should read “neither…nor” instead of “neither…or”. But I don’t get why the singular “is” isn’t incorrect here. Shouldn’t it read “are”? SparkNotes’ explanation is:

“While the “is” in choice C may sound funny coming on the heels of “intervals” and “distances,” it’s actually correct because it matches the “neither . . . nor” construction. As a parallel unit, “neither . . . nor” takes a singular verb.”

I’m not a native English-speaker - could anyone explain?
Thanks a lot! :)