Marketers make their share of errors, but they usually don’t trip over their own tubes of toothpaste. Consider this from Colgate, though:
With regular use, it removes stains that ordinary toothpaste don’t.
Yes, the box really says that ordinary toothpaste don’t.
Either the copywriter was befuddled by agreement in number or the company lost an “s” from “toothpastes” when the box was printed.
The easiest way to decide the proper number of the verb in a sentence like this is to fill in the implied word:
… that ordinary toothpaste don’t remove.
When we do that, the agreement problem becomes immediately apparent. Colgate should have said this:
With regular use, it removes stains that ordinary toothpaste doesn’t.
With regular use, it removes stains that ordinary toothpastes don’t.
I can only hope that Colgate’s toothpaste is better than its grammar.
(Thanks to Tom Eblen for passing this along.)