once-in-a-lifetime opportunity千载难逢的机会;可一不可再的机会

A Once-in-a-lifetime Offering一个曾经在一个千载难逢的产品

once-in-a-lifetime chance一期一会

once-in-a-lifetime exposure终身一次照射量

a once-in-a-lifetime experrience一生中难得的经历

a once-in-a-lifetime experience一生中仅有一次的经历

once-in-a-lifetime transaction仅此一次的交易

Once-in-a-Lifetime Offer终身优惠

a once-in-a-lifetime opportunity一生一次的机会