bolster spring

例句：

1. 1. The new car has a bolster spring that helps it accelerate smoothly.
   这辆新车有一个支撑弹簧，帮助它平稳加速。
2. 2. The old house needed some bolster springs to make it more stable.
   这所老房子需要一些支撑弹簧来使其更加稳定。
3. 3. The bolster spring in the door is broken, so I need to replace it.
   门上的支撑弹簧坏了，所以我需要更换它。