"That man has an older brother and an older sister."
Translation:그 남자는 형하고 누나가 있어.
My three choices were:
- 저 남자는 형과 누나가 있습니다.
- 저 남자는 형하고 누나가 있어.
- 그 남자는 형하고 누나가 있어.
They are all identical except one uses 그 rather than 저 (both of which Duo translates to "that") and one uses a more formal ending. But somehow only the last one is correct. Hmmm.
For the verb 있다 the noun should have a subject particle (이/가). It is literally saying "As for that man, an older brother and sister exist."