rate of application and time of phosphorus

例句：

1. 1. The company's profit margin is the rate at which it earns money compared to its costs.
   公司的利润率是它赚取的利润与成本的比率。
2. 2. The speed of light in a vacuum is approximately 299,792 kilometers per second.
   光在真空中的速度大约是每秒299,792公里。
3. 3. The rate of change in the population is a key factor in understanding economic growth.
   人口增长率是理解经济增长的关键因素。