ratio of freight cars under repair

例句：

1. 1. The ratioof the population to the land is1:3.
   人口与土地的比例是1:3。
2. 2. The ratio of sugar towater in this recipe is 1:1.
   食谱中糖和水的比例是1:1。
3. 3. The ratio of carbohydratesto proteins in a balanced diet is importantfor health.
   平衡饮食中碳水化合物和蛋白质的比例对健康很重要。