Fill in am/is/are/isn't/aren't

Fill in am/is/are/isn't/aren't

1. My friend is tall and thin.
2. His father is at home. He is at work.
3. Our players are fast. They are slow.
4. Their children are at the gym.
5. Is your brother a doctor? No, he isn't.
6. Are your friends strong? Yes, they are.