"경찰서에서 밥을 먹습니다."
Translation:He eats at the police station.
Hi Gerald, in Korean he/she is actually rarely used in spoken Korean. He is 그 or 걔 in spoken informal, but I recommend you avoid using he/she. Pronouns like I/you/she/he/they/we is not used often like in English. Instead of using he/she, people would understand already by the situation (like if you were talking about him earlier), or they will address them directly by name. If there is no context like in the duolingo sentence, assume it is yourself or others. It takes time to get used to like i did for me. Good luck!