back axle

例句：

1. 1.The car's back axle is worn out.
   这辆车的后轴磨损了。
2. 2. The engineer replaced the back axle with a new one.
   工程师用一个新的后轴替换了原来的。
3. 3. The old truck had a bad back axle, causing it to fall apart.
   那辆旧卡车的后轴坏了，导致它散架了。