大家好，今天我們分享一個非常有用且地道的表達——保質期， 這個短語的英文表達是：
shelf life （尤指食品的）貨架期，保質期
Fresh fruit has a very short shelf life.
新鮮水果的保質期很短。
For taste, pick something with a long shelf life like chocolate.
對於口感來說，挑一些保質期限長一些的食品如巧克力。
The actual shelf life of a pharmaceutical product might be longer than the expiration date that appears on the packaging.
藥品的實際保質期要比包裝上顯示的保質期要長。
Milk normally has a shelf life of a week.
牛奶一般有一星期的保質期。
Milk has a very short shelf life, as it tends to expire quickly.
牛奶有非常短的保質期，它很快就會過期。
I'm hoping that this product will have a very long shelf life and be useful for years to come.
我希望這個產品有非常長的保質期，對接下來的幾年會非常有用。
past-date 過期
I think this milk is past-date. You'd better throw it away!
我想這個牛奶過期了，你最好扔掉它。
It's past-date. We can't eat it.
它過期了，我們不能再吃了。