mean-free path

例句：

1. 1. The journey was full of meaningless paths and dead ends.
   这段旅程充满了无意义的道路和死胡同。
2. 2.He decided to take a mean-free path to avoid the crowds.
   他决定走一条无意义的道路，以避免人群。
3. 3. The scientist found a way to make his mean-free path more efficient.
   这位科学家找到了一种方法，使他的无意义路径更加高效。