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.