ratio call spread

例句：

1. 1. The ratio of the population to the number of jobs is a key factor in determining economic growth.
   人口与工作数量的比例是决定经济增长的关键因素。
2. 2. The company's ratio call spread strategy has been effective in reducing costs and increasing efficiency.
   公司的比率呼叫扩散策略在降低成本和提高效率方面已经取得了有效成果。
3. 3. The ratio call spread model was developed to predict the future demand for goods based on historical data.
   比率呼叫扩散模型被开发出来，以基于历史数据预测未来对商品的需求。