Grammar Check: “Can have” or “can of” ?

“Could have” or “Could of”? “Can’t have” or “can’t of”? "Would have" or "would of" ... and so on! Okay, so these are really common errors which many people make, both in writing and in speech.

Confused?

There are many similar versions of this too, such as “shouldn’t of” instead of “shouldn’t have”, or “won’t of” instead of “won’t have”. The same rule applies in each case though, and this is an easy one to fix.

Basically there is never a time when you use “could of” or “couldn’t of” or “shouldn’t of” or “won’t of”, etc. It’s never correct. You always need to use “have” instead of “of”.

I think the reason many people do this is because when they’re speaking they often say something like “could’ve”, which is a contraction of “could have”, rather than say the full expression “could have”. And while there’s nothing wrong with saying or writing “could’ve” (or should’ve or whatever), it actually sounds very similar to “could of” or “should of”, which are incorrect. So, that’s how I think some people can get a bit confused with these, and end up writing what they think they hear.

• You could have read a book instead of watching television.
• I would have gone to see the football game if the weather was better.
• He can’t have left the dog in the park, as the park was closed today.
• She couldn’t have eaten the steak because she’s a vegetarian.