It Is Never COULD OF!
by Tina Blue
August 12, 2000
CHEAP AND EASY EXPLANATION: There is no such phrase as "could of" in English. Never, never, never write those two words together as a phrase.* You don't even need to read the following explanation to know why, if you don't want to. All you have to do is to proofread your work to make sure those words never appear as a phrase in your writing.
Native speakers of English really should know better--but way too few do. In fact, I've recently read two essays that include the locution "could of." (Another covered all bets by writing "could have of.")
How can this happen, you may wonder. Easy: Say the contraction "could've" (for "could have") out loud. Hear it? It sounds like "could of," and if a person is a bit careless about his writing, he could easily write it as he hears it. But "could" is an auxiliary (helping) verb in a verb phrase. The word that it "helps" must also be a verb, of course. Is "of" a verb? Well, just try conjugating it: I of, you of, he/she/it ofs, we of, you of, they of. I don't think so.
Why did I go to the trouble of pretending to conjugate "of"? I know it's silly, but it's in keeping with my "Big Bird Theory of Education": it's easier to remember a new idea if it's attached to an eight-foot yellow bird--or something equally goofy. From now on, I bet you will think, "I of, you of, he/she/it ofs," every time you hear, say, or write "could've," and that will haul your fanny up short if you're thinking of writing "could of"!
By the way, the same goes for "should've" and "would've." But you knew that, didn't you?
Anyway, do proofread your work, please. We all make mistakes sometimes, and we don't always catch them all. In fact, this grammar and usage lady has a few typos hanging out there in various comment sections for all the world to see, and it keeps her awake at night. And we are all in a hurry, I know. But at least a little proofreading is in order, don't you think?
*The only way those words can appear together in that order is if they are parts of separate grammatical elements. EXAMPLE: She ate all she could of her mother's homemade cherry pie.