at the time that something happens

We don't own a car - we just rent one as and when we need it. 我们没有车——只是在需要的时候就去租一辆。

used to talk about how another person or thing is affected by something

As for Louise, well, who cares what she thinks. 至于路易丝嘛，哼，谁管她是怎么想的。

said to show that you do not believe something is possible

"Did you get a pay rise?" "As if!" “你加薪了吗？”“没影的事儿！”

used to describe how a situation seems to be

She looked as if she'd had some bad news. 她看上去好像有什么坏消息似的。

I felt as though I'd been lying in the sun for hours. 我觉得好像已经晒了好几个小时的太阳。

They stared at me as if I was crazy. 他们盯着我，就像看疯子一样。

in the state that something is in at the present time

Will you wait till it's finished or take it home as is? 你是等着它完全做好呢，还是就这样拿回家？

already

I'm not buying the children anything else today - I've spent far too much money as it is. 今天我不会再给孩子们买任何别的东西了——我花的钱已经太多了。

sometimes said after a figurative (= not meaning exactly what it appears to mean) or unusual expression

If he still refuses we could always apply a little pressure, as it were. 如果他还是拒绝，我们总还可以在一定程度上给他施加点压力。

starting from a particular time or date

As of next month, all the airline's fares will be going up. 自下月起，所有航空公司的机票价格都将上调。

about

He was uncertain as to which road to take. 他拿不准该走哪条路。

There's no decision as to when the work might start. 至于工作什么时候开始，还没有作出决定。

changing the subject to

As to where we'll get the money from, we'll talk about that later. 至于到哪儿去搞到这笔钱，我们以后再说吧。