lifetime
/ˈlaɪftaɪm/noun
1- the duration of a person's life（人的）一生, 毕生：
a reward for a lifetime's work.
对毕生工作的回报。
1.1
- the duration of a thing's existence or usefulness（事物的）存在期; 有效期; 使用寿命：
it may well take the lifetime of a Parliament to put things right.
拨乱反正很可能需要整整一届议会的努力。
1.2
- informal used to express the view that a period is very long〈非正式〉漫长的一段时间：
five weeks was a lifetime, anything could have happened.
五个星期简直就是漫长的一生, 什么事情都已可能发生。
短语
of a lifetime
- (of a chance or experience) such as does not occur more than once in a person's life（机会, 经历）终生难遇的, 一生只有一回的：
because of Frankie she had rejected the opportunity of a lifetime.
都是因为弗兰克, 她才放弃了千载难逢的机会。