David，is that man your Chinese teacher?—It___________ be him．He’s having a meeting．

Our Chinese teacher is very kind to us. So we all regard her _____ our best friend. [ ]

There are _____________ people in the supermarket. It’s so crowded.

The student is _________ see the teacher because he_________a mistake.

Who are you going sightseeing______?—My parents.[ ]