To forbid the cheating strictly in this important exam, the authorities have released a rule that students _________ bring any reference books and stationery into their classrooms.

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

 --Will you read me a story, Mummy?--OK. You ________have one if you go to bed as soon as possible.

— I didn’t care about what other people thought about me.— Well, you ________.

The river smells terrible. People_______ dirty things into it .