28. A. learn B. know C. enjoy D. teach
27. A. patient B. tired C. special D. worried
26. A. sometimes B. never
C. often D. regularly
25. A. playing B. working
C. relaxing D. singing
24. A. built B. arranged C. designed D. formed
23. A. think of B. think over
C. think on D. think through
22. A. show B. type
C. explanation D. example
21. A. down B. at C. off D. up
20. A. so B. while C. and D. but
19. A. impressive B. impossible
C. normal D. public