21 A his son was not as thrilled by the roller coaster ride as expected

22 D even if they are exposed to more and more kinds of entertainment

23 C ever-changing thrilling forms of recreation

24 C creating more stimulating activities for them

25 A adjusting the pace of life and intensity of stimulation



26 C corporate loyalty

27 C not setting up long-term goals for their companies

28 C a higher rate of unemployment

29 B making monetary contributions to decision-makers

30 D to urge the middle class to wake up and protect their own interests



31 C settle the dispute on stem cell research quickly

32 A interested businesses and individuals

33 D have to raise money to build separate labs

34 A human stem cells are used in the research

35 B he did not want to offend its opponents



36 D tenants renting a house over a year

37 B appropriate housing may not be readily available

38 C tenants have done damage to the house

39 D to make it easier for the State Assembly to pass the bill

40 A both bills are likely to be made state laws (编辑:赵露)