她经常一时冲动买衣服。

She often buys clothes ___on ___impulse.

他一时冲动辞了职，立刻就后悔了。

He quit his job ___on ___impulse and immediately regretted it.

被怀旧情绪淹没，她一时冲动预订了回家的航班。

Overwhelmed by nostalgia, she booked a flight home ___on ___impulse.