求翻译：长期以来，美国汽车市场被三大汽车公司所垄断（通用汽车公司占42％、福特汽车公司 占28％、克莱斯勒占11％），其中通用的凯迪拉克则是“世界标准”，具有引领世界豪华车潮 流的地位。然而，到了80年代，时过境迁，美国三大汽车公司的市场份额下降至67．8％， 而凯迪拉克在豪华车市场的份额和声誉不仅面临着国内竞争者的挑战，而且还受到来自欧洲 及亚洲的竞争者的威胁。凯迪拉克车在市场上腹背受敌，它面临的问题有：产品是否定位在 合适的市场上？它的形象适合凯迪拉克汽车购买者所追求的口味吗？广告是否有效地到达了 目标市场并传递了适合的形象﹖是什么意思？

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Long-term, the United States automobile market is the 3 largest car company General Motors company monopoly (42 per cent, Ford Motor Company, Chrysler accounted for about 28 per cent 11 per cent), of which the Cadillac is the "world standard" with a world-leader in luxury car tide flow. However, in

Long time, United States car market by the big three companies that monopoly (General Motors, Ford Motor Company, 28% 42%, Chrysler, 11%), in which GM's Cadillac is "standard of the world", have the status of lead the trend of luxury cars in the world. However, in the 80 's, time, United States the