21: A. excellent B. beautiful C. determine D. similar

20: A. social B. signal C. teacher D. suppose

19: A. complete B. command C. common D. community

18: A. habitat B. inflation C. disease D. remove

17: A. between B. working C. teacher D. lovely

16: A. newspaper B. dedicate C. timetable D. commercial

15: A. prepare B. divide C. attract D. differ

14: A. polite B. system C. progress D. children

13: A. provide B. machine C. lesson D. important

13: A. provide B. machine C. lesson D. important