"The man" was marked wrong.

one of the worst things about this course is how the style guide seems to have been 그 = 'that', not 'the', so 99% of the time there's just no definite article & it's pure guesswork whether they translated it as The, A, or nothing at all

How do we know if it's "a" or "the"? It feels like the criteria changes from exercise to exercise...

That is so sad.

or maybe a cat lost its owner? :)

The man forgot the cat

If I understand correctly, the 버리다 is a compound verb strategy of making the main verb perfective. So, this sentence is especially sad because I think it is implying the cat is (presumed) lost for good. Please, correct me if I'm wrong.