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.