12. Mrs. Brown was much disappointed to see the washing machine she had______went wrong again.

A. it repair　 　　 B. it repaired　　　 C. had repaired　　　 D. to be repaired

11. ---What is our earth like ________from the moon?

---Well, our earth, with water ________ 70% of its surface, appears as a "blue ball".

A. seen; covering　　　　　　　　　　　　　　　 B. seen; to cover

C. seeing; covered　　　　　　 　　　　　　　　D. seeing; covering

10. I’d rather have a room of my own, however small it is, than　　　 a room with others.

　　 A. to share　　　 B. to have shared　　 C. share　　　　　　　　 D. sharing

9．It was raining heavily. Little Mary felt cold, so she stood_____ to her mother.

　　 A. close　　　 B. closely　　　　　　　　 C. closed 　　　　　　 D. closing

8. The teacher couldn’t make himself　　　　 attention to because the students were so noisy.

　　 A. to pay　　　　 B. to be paid　　　　　 C. paid　　　　　　　 D. pay

7. My father served in the army in 　　　　when he was in 　　　　.

　 A. 1950s; twenties　　　　　　　　　　　　　　　 B. the 1950s; his twenties

　 C. the 1950s; the twenties　　　　　 　　　　　　 D. 1950s; the twenties

6.-Would you like me to carry this box for you?　

　-_________.I can manage it myself.

A. No, thanks　　　　　　　　　　　　 B. It's a pleasure

C. That would be nice　　　　　　　　 D. Yes, please

22.(20分)图6所示为一种记录地震的摆，摆球m固定在边长为L，质量可忽略不计的等边三角形框架的顶点A上，它的对边BC跟竖直线成不大的夹角a，摆球可绕固定轴BC摆动。求摆球做微小摆动的周期。

21. (12分)一列简谐横波由质点A向质点B传播。已知A、B两点相距4 m，这列波的波长大于2 m而小于20 m，下图表示在波的传播过程中A、B两质点的振动的图像，求波的传播速度。

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