广告主的广告投放有明显向除中心城市以外的二三级市场转移的趋势。出现这种趋势的原因有两方面:一是企业发展的客观规律。企业的市场拓展一般遵循从中心向四周辐射的规律。一级市场容量有限而且竞争激烈,随着企业规模的扩大,二三级市 Advertisers advertising significantly to the second and third tier cities outside the center of the transfer market trend. There are two reasons for this trend: First, the objective law of enterprise development. Enterprises generally follow the market expansion from the center of radiation to the law. First-tier market capacity is limited and highly competitive, with the expansion of business scale, 23 cities