56、B It will protect them from sunburn

57、A I is ineffecitive in preventing melanomas

58、D Daily application of sunscreen helps reduce the incidence of melanomas

59、C It is not based on sirect observation of the subjects

60、A A Using both covering up and sunscreen.

61、B well-educated people tend to work longer.

62、B A rapid techonological advwnce.

63、A Economic groth will slow down.

64、C Even wealthy people must work longer to live comfortably in retirement .

65、D Skills are highly valued regardless of age.