The car of (them/their) is just amazing!
What should I use, possessive pronoun or objective case I like a thing of them/someone is sounding good to me.yet I'm perplexed!
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Sign up to join this community"Theirs" is to be used here.
But you can use both of the following:
The car of theirs is just amazing!
Their car is just amazing!
Their is subject, them is object. You would mostly use 'them' at the end of a sentence i.e. something is done to them, or I took the car belonging to them. The word 'Their' always precedes something which belongs to 'them'. i.e. Their Car their holiday etc. I hope this makes it a little clearer.