—_____ do you play computer games?
—Twice a month.
| A．How long | B．How many |
| C．How often | D．How much |
________ of the students in our class is 64, and ________ of them are girls.
| A．The number ; one third | B．A number; one third |
| C．The number; two third | D．A number; one second |
I ______ along the road when suddenly someone patted me on the shoulder from behind.
| A．walked | B．had walked |
| C．was walking | D．would walk |
We are told ________ everywhere. It’s our duty to keep our school clean.
| A．not to make much noise | B．to throw waste paper |
| C．to draw | D．not to spit |
---Mind your steps, guy! Don’t you see the words “__________ the grass”?
| A．Keep off | B．Keep out |
| C．Take off | D．Take out |
Nobody can learn English well __________he works hard on it.
| A．if | B．unless |
| C．when | D．but |