a. I met Tom's ex-wife at a dinner party last night.
Could one use that sentence if one knows that Tom has more than one ex-wife and one hasn't been talking about a particular ex-wife? So context does not clarify which ex-wife I am talking about. I just say the sentence out of the blue.
I think the correct way would be to say:
b. I met one of Tom's ex-wives at a dinner party last night.
But I think people would use (a) instead of (b).
Many thanks
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