直线性

例句：

1. 1. The line of the road is straight as an arrow.
   这条路线直得像箭一样。
2. 2. The car's steering wheel is very straight.
   汽车的方向盘非常直。
3. 3. The path is very straight and easy to walk.
   这条小径非常直，走起来很方便。