16. 　　different kinds of pianos, the workers farther improved their quality　

A. To produce　 　 B. Being produced 　　 C. Produced 　 　　 D. Having produced

15. A person 　　a foreign language must be able to use the foreign language 　　　all about his own.　

A. to learn, to forget 　　　　　　　B. learning, to forget　

C. to learn, forgetting　 　　　　　D. learning, forgetting

14. The wallet 　　several days ago was found 　　in the dustbin outside the building.　

A. stolen, hidden　　　　 B. stealing, hiding　　　 C. stealing, hidden　 　 D. stolen, hiding

13. Lessons 　　　　　easily were soon forgotten.　

A. to learn　　　　　 B. learn　 　 C. learned　　　 D. learning

12. The ground is 　　　　with 　　　　　leaves.　

A. covering, falling 　　 　B. covered, falling　 C. covered, fallen 　D. covering, fallen

11. The library's study room is full of students 　　　　　for the exam.

A. busily prepared　 B. busy preparing　C. busyly prepare 　D. are busily preparing

10. The scientists were waiting to see the problem 　　　　.　

A. settle　　 　　 B. settled　　 　 C. to settle　　 D. settling

9. The foreigner tried his best, but he still couldn't make his point 　　.

A. understand　 　　　　 B. understanding 　　　 C. to understand 　 　　 D. understood

8. People 　　　　in the city do not know the pleasure of country life.

A. live　　 　　　 B. to live　　 　 C. lived　　 　　 D. living

7. The 　　　　　price will save you one dollar for each dozen.

A. reduce　　 　 B. reducing　　 　　　 C. reduced　　 D. reduces