percentage of net ton kilometres to gross ton kilometres

例句：

1. 1.The company's profit margin is 20% of its revenue.
   该公司的利润边际是其收入的20%。
2. 2.The cost of living in this city is 30% higher than in the next town over.
   这个城市的生活成本比下一个城镇高出30%。
3. 3. The teacher explained the percentage of students who failed the test to the class.
   老师向全班解释了考试失败的学生比例。