"고양이는 무엇을 먹습니까?"
Translation:What do cats eat?
More like "What does a cat eat?" But the original comment is correct - since Korean doesn't have definite or indefinite article, the meaning isn't unambiguous without context. The speaker could be looking at a cat eating something and use the same sentence to mean "What does the cat eat?" or "What is the cat eating?" (since Koreans often prefer simple present tense to the progressive).