spontaneous braking

例句：

1. 1. The car's spontaneous braking saved the driver from a serious accident.
   汽车的自发刹车救了司机免遭一场严重的事故。
2. 2. The sudden stop of the train was caused by a spontaneous braking system.
   火车突然停下来是因为一个自发刹车系统。
3. 3. The brakes on this car are very sensitive, which means it can spontaneously brake when needed.
   这辆车的刹车非常灵敏，这意味着它需要在需要时自发地刹车。