linear explanatory economic model

例句：

1. 1. The pathis linear and easy to follow.
   这条路线是直线的，很容易走。
2. 2. The datais linearly proportional to the temperature.
   数据与温度成正比例关系。
3. 3. Theline of cars is linearacross the street.
   汽车线在街道上是直线的。