В первом предложении пропущено местоимение, потому на выбор:
1. What are you/we/they doing next Friday? / What is he/she doing next Friday?
2. He is going to work for his father when he leaves school.
3. They are having a party tonight.
4. He is playing in a football match this afternoon. Let's watch him.
5. I'm tired. I am going to sleep this afternoon.
6. We are flying to America tomorrow morning. Look! Here are the tickets.