—____ do the students exercise a week? —Once or twice.
A. How often B. Hong long C. How many times.
---How often are the Olympic Games held？ ---_____four years.
| A．Every | B．Each | C．In | D．For |
The ice isn’t ______________ to skate on.
| A．thin enough | B．enough thin | C．thick enough | D．enough thick |
---Are you going to ____________ your friends to your party?
---Yes, sure.
| A．like | B．want | C．make | D．invite |
---Must I clean the floor now?
---__________. It is too dirty.
| A．Yes, you needn’t | B．No, you needn’t |
| C．No, you mustn’t | D．Yes, you must |
---How long may I _____________ the book?
---Two weeks.
| A．borrow | B．lend | C．buy | D．keep |