Điền động từ be thích hợp

11. The teacher
12. The students
13. One student
14. We
15. He
16. I
17. You
18. She
19. He
20. It
21. The children
nice.
very clever.
in the classroom.
sorry for him.
tall and thin.
happy.
at the zoo this morning.
in London last week.
on the beach last weekend.
cold yesterday.
at the zoo.