Q: I was on Facebook the other day when this ad popped up: “Are you smarter then the President? Take our IQ test to see.” I see this “than/then” mistake more and more, and it drives me crazy (not a far drive – more like walking distance). I know languages evolve. Should I just relax and accept this vowel movement?

A: You’re right, of course, that English is always evolving, but not in this case. The words “than” and “then” are similar only in the way they sound.

I explain the difference between them this way in my grammar book Woe Is I: “If you’re comparing or contrasting things, use than, as in more than or less than. If one thing follows or results from another, use then (as in, Look, then leap).”

Here’s an example I give of the two words at work: The next morning, Paolo was sicker than a dog. He took some aspirin, then went back to bed. “If gin disagrees with you, then avoid it,” said Francesca.

As I say in Woe Is I, if a sentence like “He’s taller then his brother” doesn’t make your hair stand on end, you should go stand in the corner. Not you, of course! But you might be interested in a blog item I wrote last summer about “than I” versus “than me.”

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