求"as and when"的确切含义?例句：The information will be updated as and when it is necessary. 到了必要的时候,这条信息会更新的.

求"as and when"的确切含义?例句：The information will be updated as and when it is necessary. 到了必要的时候,这条信息会更新的.
求"as and when"的确切含义?
例句：
The information will be updated as and when it is necessary.
到了必要的时候,这条信息会更新的.

求"as and when"的确切含义?例句：The information will be updated as and when it is necessary. 到了必要的时候,这条信息会更新的.
实际上是两个从句,相当于as it is necessary and when it is necessary
相当于如果必要的话,或者是有必要的时候

就是表示假设关系的时间段或时间点
也就是说 如果在什么什么时间

as and when 就是到时候；到必要的时候的意思
给你看个例句吧：
We'll decide on our team as and when we qualify for the competition. 我们来决定自己的队到什么时候才有资格参加比赛.

由when, while, as引导的时间状语从句。例如：
When you think you know nothing, then you begin to know something.当你以为自己一无所知的时候，你就是在开始知道一些事物了。
When truth is buried under the ground it grows, it chokes, it gat...

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由when, while, as引导的时间状语从句。例如：
When you think you know nothing, then you begin to know something.当你以为自己一无所知的时候，你就是在开始知道一些事物了。
When truth is buried under the ground it grows, it chokes, it gathers such an explosive force that on the day it bursts out , it blows up everything with it.当真理被埋在地下的时候，它在生长，它感到压抑，它蓄存着这么一种爆炸性力量，一旦冒出，它就会炸破一切！
Strike while the iron is hot. 趁热打铁。
Will you watch my clothes while I have a swim. 我游泳的时候，请你照看一下我的衣服。
You can feel the air moving as your hand pushes through it. 当你的手在空气中挥动的时候，你就能感觉到空气在流动。
Our headmaster laughed as she spoke.我们的校长边谈边笑。
【区别】when, while和as的区别：when引导的从句的谓语动词可以是延续性的动词，又可以是瞬时动词。并且when有时表示“就在那时”。例如：
When she came in, I stopped eating.她进来时，我在吃饭。(瞬时动词)
When I lived in the countryside, I used to carry some water for him.当的住在农村时，我常常为他担水。（延续性的动词）
We were about to leave when he came in.我们就要离开，就在那时他进来了。
While引导的从句的谓语动作必须是延续性的，并强调主句和从句的动作同时发生（或者相对应）。并且while有时还可以表示对比。例如：
While my wife was reading the newspaper, I was watching TV. (was reading是延续性的动词，was reading和was watching同时发生)
I like playing football while you like playing basketball.我喜欢踢足球，而你喜欢打篮球。（对比）
As表示“一边……一边”，as引导的动作是延续性的动作，一般用于主句和从句动作同时发生；as也可以强调“一先一后。例如：
We always sing as we walk.我们总是边走边唱。（as表示“一边……一边”）
As we was going out, it began to snow.当我们出门时，开始下雪了。（as强调句中两个动作紧接着先后发生，而不强调开始下雪的特定时间）

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