spontaneous sweating due to deficientcy of blood

例句：

1. 1. The spontaneous decision to volunteer for the charity event was a brave one.
   自发决定为慈善活动做志愿者是一个勇敢的决定。
2. 2. The spontaneous outburst of anger from the crowd was unexpected.
   人群中突然爆发出愤怒，这是出乎意料的。
3. 3. The spontaneous act of kindness by the stranger saved the child's life.
   陌生人的自发善举拯救了孩子的生命。