—Must we clean the classroom now?
—No ,you _______.
| A．must | B．needn’t | C．aren’t | D．mustn’t |
My parents usually take a walk ______ dinner to keep healthy.
| A．at | B．of | C．during | D．after |
I’m expecting a digital camera for long, but dad has no time to buy ______ for me.
| A．it | B．one | C．this | D．that |
— Who’s that lovely girl?
— You mean ______ girl with long hair? That’s Kate.
| A．a | B．an | C．the | D．不填 |
I think _____ very important for students to study by themselves in the school or at home.
A. it B. this C. that
Could you please tell me_?
A. why does the earth go around the sun
B. why the earth goes around the sun
C. why the earth went around the sun