A possible reason for the sympathetic tone is that upward mobility can no longer be taken for granted.

也许出现这种同情的语调还有另一个原因，那就是向上层社会爬不再是种理所当然的想法。

The rate of action potentials travelling through each division is known as your " sympathetic tone" and your " parasympathetic tone."

动作电位通过每个分区的速率被称为“交感神经张力”和“副交感神经张力”。