You must stop and wait for your turn when you see the sign______.
A. 
B. 
C. 
We ________ a sports meeting if it is fine next Wednesday.
| A．have | B．had | C．have had | D．will have |
I think Book 6 is ________ than Book 5.
| A．much difficult | B．very difficult | C．more difficult | D．the most difficult |
She kept _________ hard at her physics and finally caught up with us.
| A．work | B．worked | C．working | D．to work |
--- ________ you play international chess?
--- No, I can’t. But I can play Chinese chess.
| A．Must | B．Need | C．May | D．Can |
--- __________ are all these together?
--- 425 yuan.
| A．How much | B．How many | C．How long | D．How often |