Does B's reply sound natural in the following dialogue? Here, he is obviously denying he has an invisibility cloak to show he doesn't believe John has a Cadillac. Are there any constraints on this pattern? Some people say I should begin the main clause with "I am . . . " with this pattern to indicate absurdity. Is that necessary?
A: Did you know John owns a Cadillac?
B: If he owns a Cadillac, I own an invisibility cloak.
I am wondering whether there is a punchiness requirement on the main clause of this pattern.
Compare the following sentences:
- If that's Princess Anne, then I'm able to fly from Zurich to San Francisco in just under two hours and wenty minutes.
- If that’s Princess Anne, I’m a Dutchman.
- If John owns a Cadillac, I own an invisibility cloak.