I was wondering if it is grammatically correct to say, "I was mistaking it with something"?

For example: some animal is coming from far away towards you and you think it is a cat. When it is near, you realize it is a dog; so you say to a friend "I was mistaking it with a cat!".


5 Answers 5


You can say that, and it might pass as grammatically correct (I agree with @Ronald's answer about using for rather than with); however, I think the simple past would sound more natural:

I mistook it for a cat!

Your sentence uses the past progressive (or past continuous) tense, which is used to talk about actions that continue for a period of time. You might use that tense in a sentence like this one:

I was thinking it was a cat, when all of a sudden it barked!


The expression is to mistake somebody/something for, NOT to mistake somebody/something with. The use of with gets a zero return on Google Books Ngram viewer.

There is a similar expression to take somebody/something for that means much the same thing.

It's possible to use with after take in a different context, as in I took his advice with a pinch of salt, which means something quite different.

  • 3
    Or you'd get the usage of "with" if instead of mistaking it you were confusing it. Dec 19, 2018 at 16:00
  • Although, ironically, most uses of "confused with" should actually have been "conflated with" ;o) Dec 20, 2018 at 12:58

First, the approriate preposition is "for" as was pointed out R Sole.

Second, it would be much more frequent to hear from a native speaker "I mistook" rather than "I was mistaking." The latter would not sound idiomatic to a native speaker except in cases where the continuing nature of the mistake was being emphasized:

"I was mistaking it for a cat all the while, up until it barked, that is."

In most cases, the simple past should be used rather than the past progressive.

  • It depends a little on the context (what doesn't? :o)) but I find I most often find myself referring to a misunderstanding in the past tense with either I misunderstood… (in a sense synonymous with I mistook you ... i.e. I got the wrong end of the stick) or I was confusing ... (possibly had confused) because this usually comes after some time of conversation before it dawns on me that I erred! tl;dr I find the progressive usually more appropriate to what has just occurred ;o) Dec 20, 2018 at 12:56
  • 1
    I do not disagree that it depends on context. In fact, I pointed out that the past progressive could be appropriate. And it is a nice point about "confuse." Because "confusion" implies duration whereas "mistake" implies a singular event, the choice of tense may well be affected by the slight difference in meanings. I will not try to dispute what is a valid and interesting point, but, given the apparent knowledge of English by the OP, I doubt it helpful to take it into account in my answer. Dec 20, 2018 at 13:56
  • Touché. Yes, I think your explanation is correct - the choice of verb tends to suggest the tense. Dec 20, 2018 at 14:01

It's "mistake for" or "confuse with". I don't know if any grammatical rules control this. I'm a native speaker, and that's just the way it is.

"I was mistaking it for a cat"

"I was confusing it with a cat"

The difference in meaning is small. You might say either when you realize that your eyes are tricking you.


Maybe it's better to use word confused:

I was confused cat with dog.

Right version (credits to @TannerSwett) :

I confused the dog for a cat


I was confused between a cat and a dog

And one more:

I totally was confused by cats and dogs.

Cats and dogs confused me.

There is a lot of confusion in cats and dogs.

Cats and dogs are so confusing.

  • 3
    No, you can't say "I was confused cat with dog", at least not where I live. But you can say "I confused the dog for a cat" or "I was confused between a cat and a dog". Dec 19, 2018 at 14:35
  • Where I live, "I confused the dog FOR a cat" could only mean something like "I made the dog confused, for some reason which involved a cat" (and obviously, that sentence needs more context before it makes much sense!).
    – alephzero
    Dec 19, 2018 at 16:12
  • Every single option you gave is inferior and has problems. The first is not even grammatically correct. In the second, "confused" is transitive so you are confusing the dog (what did you do, spin it around?). In the last one, it's extremely unclear what you were confused about. It could even mean that you were you confused while standing between a cat and a dog.
    – T Nguyen
    Dec 19, 2018 at 18:07
  • @TNguyen, so what is right phrase with confusion word? I'm completely confused.
    – Alexan
    Dec 19, 2018 at 18:33
  • @TannerSwett version is the best, most idiomatic use of "confuse" in this context.
    – T Nguyen
    Dec 19, 2018 at 19:20

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