One of the rules is that every student ________ wear school uniform while at school.

He has poor _______, so he can’t see the words on the blackboard clearly.

It was so dark outside that the little child ________ go out by himself. 

There are no customers in the hotel. It ______ have the friendliest service.

---Look!It _______ be Mr Zhang . ---No,it _______ be Mr Zhang. He has gone to Paris .