The students are ______ to hand in the exercises before class.

— Food problem is becoming a big one in China! —I think the food ________ before going to shops or supermarkets. 

The stones are so heavy. How _____ they _____ to the top of the building without modern machines?

---Please say“I’m here．”when your name _________.---Yes，Mr Smith．

Excuse me. When can we play badminton at the court?  Not until it _______ next week.