when meaning in English
adv.
1.〔疑问〕什么时候，几时。 W- did you see him (这以前)你几时见他的？
2.〔关系，引导定语从句〕当…的时候。 He came at a time when I least expected him. 他在我最想不到的时候来了。
3.从前境况差时。brag of having known sb. when 夸耀自己是某人过去的患难之交[布衣之交]。
1.当…的时候。
2.(刚)…就…。
3.如果。
4.然后。
5.既然。
6.可是，却。
短语和例子
pron.
1.〔疑问〕什么时候。Till when can you stay 你可以待到什么时候？
2.〔关系〕那时。 They left on Monday, since when we have heard nothing. 他们星期一动身，以后就没有消息了。
n.
时候，时间，日期，场合。 the when and the where 时间和地点。
Examples
- His problem began when he was a child .
他的这个问题起始于孩提时代。 - When hard tactics failed , soft methods were used .
硬的不行来软的。 - I was just going to speak, when the bell rang .
我刚要讲，钟就响了。 - When can you take delivery of the car ?
你什么时候才能收到那辆汽车？ - When the boss falls from power , his lackeys disperse .
树倒猢狲散。