Howoldis“old”?Theanswerhaschangedovertheyears.TwoHundre...
问题详情：Howoldis“old”?Theanswerhaschangedovertheyears.TwoHundredyearsago,youwereoldat35.Atthebeginningofthe20thcentury,theaveragelifespan(平均寿命)was45.In1950,70-year-oldswerereallyold.Today，ahealth...