独轮车

例句：

1. 1. I need to buy a new bike for my son's birthday.
   我需要为儿子的生日买一辆新的自行车。
2. 2. The old lady rode her single-wheeled bicycle to the park every morning.
   那位老太太每天早晨骑着她的单轮自行车去公园。
3. 3. The kids enjoyed riding their single-wheeled bicycles on the beach.
   孩子们在海滩上骑着他们的单轮自行车玩得很开心。