linear homotopy

例句：

1. 1. The line of the road is straightas an arrow.
   这条路线直得像箭一样。
2. 2. The data is linearly proportional tothe amount of light.
   数据与光线量成正比例关系。
3. 3. The graph is linearlyrelated to the temperature.
   这个图与温度呈线性关系。