castor axle

例句：

1. 1. The castor axle is the main part of the car's suspension system.
   小马车轮轴是汽车悬挂系统的主要部分。
2. 2. The engineer had to replace the castor axle with a new one.
   工程师不得不用一个新的小马车轮轴来替换原来的。
3. 3. The old castor axle broke during the race, causing the team to lose valuable time.
   在比赛中，旧的小马车轮轴断了，使队伍失去了宝贵的时间。