1)useful life,有用期限2)fixed lifetime,有限使用期3)expriation data,做用限期，有效期4)Content period of validity,有效使用期限5)validity of L/C,信用证有效期限6)useful life,有效寿命，使用寿命，使用期限，利用期限，缆有效期
用法和例句
篊ement is o ne of the most important material in project construction，Afterstudying the law of variable demand of fixed lifetime materials such as cement，we promptan optimal ordering policy model.
