一、while
n. 一会儿, 时间
conj. 当...的时候, 虽然
vt. 消磨
1) A period of time:
一段时间：
stay for a while;
停留下会儿；
sang all the while.
一直都在唱歌
2) The time, effort, or trouble taken in doing something:
费时：做一件事情的花费时间、努力或工夫：
The project wasn't worth my while.
这项方案不值得我花工夫，
3) conj.做连接词
As long as; during the time that:
只要；在…时间里：
It was lovely while it lasted.
当它开着的时间它是很惹人喜爱的
4）At the same time that; although:
在…同时；尽管，虽然：
While the grandparents love the children, they are strict with them.
“虽然祖父母们都爱他们的孩子，但却对他们要求严格”
5）Whereas; and:
然而；而，而且：
The soles are leather, while the uppers are canvas.
鞋跟是皮的，而鞋面是帆布的，
6）v.tr.做及物动词
whiled， whil.ing， whiles
To spend (time) idly or pleasantly:
消磨：闲散或轻松地消磨时间：
while the hours away.
消磨时光
二、 when
conj.
就在那个时候, 在...的时候
adv.
什么时候, ...的时候
pron.
什么时侯, 那时
1，作adv.副词表示
At what time:
什么时候：
When will we leave?
我们什么时候离开?
2，作conj.连接词表示
At the time that:
在…的时候：
in the spring, when the snow melts.
在春天，当雪融化的时候
As soon as:
一…就…：
I'll call you when I get there.
我一到那里就给你打电话
Whenever:
无论什么时候：
When the wind blows, all the doors rattle.
只要风一吹，这门就吱嘎作响
During the time at which; while:
在…期间，当…时：
When I was young, I was sick all the time.
在我小时候我总是生病
Whereas; although:
虽然，尽管：
She stopped short when she ought to have continued.
尽管她应该继续下去，她却突然停住了
Considering that; if:
考虑到，如果：
How can he get good grades when he won't study?
他不用功的话怎么拿高分呢?
3，作pron. 代词
What or which time:
什么时候：
Since when has this been going on?
从什么时候起事情象这样?
4，作n.名词用表示
The time or date:
时间或日期：
Have they decided the where and when?
他们已经定下来地点和时间了吗?
三、as soon as 固定搭配，一 ---- 就 ----
i'll call you as soon as when i arrive there.
我一到哪里就给你打电话。
四、as
adv. 同样地, 被看作, 象
prep. 当做
conj. 与...一样, 当...之时, 象, 因为
1, 作adv.副词
To the same extent or degree; equally:
同等地，一样地：同一限度或程度地；同等地：
The child sang as sweetly as a nightingale.
这孩子歌唱得同夜莺般婉转
large carnivores, as the bear or lion.
大的食肉动物，如熊或狮子
2，作conj.连接词
To the same degree or quantity that. or as :
像，如同：同等的程度或量，
You are as sweet as sugar. The situation is not so bad as you suggest.
你甜如蜜。情形不如你说的那样糟
In the same manner or way that:
以同样方式，以同样方法：
Think as I think.
像我这样去想
At the same time that; while:
同时；当…时：
slipped on the ice as I ran home.
我跑回家时在冰上滑了一跤
For the reason that; because:
由于；因为：
went to bed early, as I was exhausted.
睡得早，因为我精疲力尽了
With the result that:
结果：
He was so foolish as to lie.
他太傻才会撒谎
Though:
尽管：
Great as the author was, he proved a bad model. Ridiculous as it seems, the tale is true.
这位作者尽管了不起，到头来却成了一个坏榜样。这个故事看似荒唐，却是真的
In accordance with which or with the way in which:
根据或按照这一方法：
从上面的分析，你可以看出来，在有些时候他们的含义是相同的，只是各自侧重点不同而已。
参考资料：http://iask.sina.com.cn/b/5687992.html?from=related