9. Could of or could have
“Could have” is used to express something that could have happened in the past, but it didn’t. “Could of” doesn’t exist. The mistake originated from “could have” contracted form – could’ve – pronounced similar to could of. It is rarely seen in written form, because once you see it written down, you realize that it doesn’t make any sense. Unfortunately, it is pretty common in spoken language and teeth-grindingly painful to see it written.
