It is said that the gravity on Mars is only about __________ of the gravity on earth．
A. three-eighthsB. third-eighth
C. three-eighthD. third-eighth
While Helen _____ along the river after supper, she ____ a wallet lying on the roadside.
A. was walking; was finding B. walked; found
B. walked; was finding D. was walking; found
I stopped the car ____ a short break as I was feeling tired.
A. takeB. taking C. taken D. to take
______ the students were when they heard the rock music!
A. How excited B. How exciting
C. What excited D. What exciting
______ you keep trying till the end, you will never know how strong you are!
A. Although B. If
C. Unless D. Because
---Look! The light is still on. Is Mr Wu working in his office？
---No, it _____ be Mr Wu. He has gone to Nanjing for a meeting.
A. needn’t B. mustn’t
C. can’t D. wouldn’t
