linear operator

例句：

1. 1.The path is linear and easy to follow.
   这条路线是直线的，很容易跟随。
2. 2. The data islinearly proportional to the input.
   数据与输入成正比例关系。
3. 3. Theline of cars is linear across the street.
   汽车线穿过街道是直线的。