If something rarely happens, it does not happen very often.
seldom , hardly ever
They battled against other Indian tribes, but rarely fought with the whites.
他们与其他印第安部落交战,但很少与白人作战。
Money was plentiful, and rarely did anyone seem very bothered about levels of expenditure.
那时候资金丰厚,似乎很少有人很在意开支的水平。
Adolescent suicide is rarely an impulsive reaction to immediate distress.
青少年自杀决不是对一时的痛苦和不幸所作的冲动反应。