18. The use of sound is widespread as ?____? of animal communication.?
A. a meansB. waysC. a toolD. signals?
19. There is no ?____? evidence to date that people in the Western world can control their dreams, at least in experimental situations in a lab.?
A. solidB. hardC. goodD. fine?
20. Many of the inventions that made people ?____? and have determined the direction of American industry were related to agriculture and food production.?
A. affluentB. abundantC. sufficientD. bankrupt?
21. They ?____? a coin to decide who would go first.?
A. tickedB. tiledC. towedD. tossed?
22. You should ?____? to one or more weekly magazines such as Time,or People.?
A. subscribeB. orderC. prescribeD. reclaim?
23. No one knew the man’s age until he ?____? it by accident.?
A. displayB. revealedC. exhibitD. exposed?
24. Rising from the table he ?____? his hat and went out.?
A. put onB. dressedC. had onD. wore?
25. His hard work ?____? him a good reputation.?
A. obtainedB. acquiredC. gainedD. earned