איך להגיד באנגלית - אני חושבת שזה ההפך?

i think it's the opposite.

i think it's the opposite.

i think it's quite the opposite
i think it's quite the reverse
i think it's the other way around (האנגלים אומרים the other way round גם)
i think you got it totally backwards

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on the contrary תשמעי הרבה