I'm teaching conversational English to ESL students in Korea, but I don't have a strong background in grammar. I can tell them how we say things, but cannot always explain why it is that way. Today, one student asked about the phrase:

**"What does he do?"**

They wanted to know why we use "**do**" at the end, and why we cannot say "What does he **does**?". I really wanted to answer their question, so I told them I'd answer tomorrow. Please let me know! Thank you!