single route

例句：

1. 1.The single-use plastic bags are banned in the city.
   这个城市禁止使用一次性塑料袋。
2. 2.She is a single woman who has never married.
   她是一个从未结婚的单身女性。
3. 3.There is only one way to solve this problem.
   解决这个问题只有一种方法。