It is hard to believe that automobiles, radios, motion pictures, frozen foods, electric refrigerator, to mention only a few items, have come into common use within thirty years.

• 很难相信如汽车、广播、电影、冰冻食品、电冰箱等现代产品能在过去短短三十年间如此普及,而这些仅仅是冰山一角。