upward mobility

例句：

1. 1. The company's upward mobility in the market has been a key factor in its success.
   该公司在市场上的向上流动性是其成功的关键因素。
2. 2. The upward mobility of the economy is closely linked to the growth of exports.
   经济的向上流动性与出口增长密切相关。
3. 3.The upward mobility of the population is a concern for policymakers as it affects the labor market.
   人口向上流动性是政策制定者关注的问题，因为它影响劳动力市场。