[ (h)wen ] 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 Come when you please. 你高兴的时候来好啦。 I was just going to speak, when the bell rang. 我刚要讲，钟就响了。 Why use wood when you can use plastic 既然能用塑料，何必非用木料？ Please ring me up when she comes. 如果她来了，请打电话给我。 I stayed till noon, when I went home. 我留到中午，然后就回家了。 We have only three books when we need five. 我们要五本书，可是只有三本。 He walks when he might ride. 可以坐车，他却走路。 when all comes to all 结果。 when due 到期时。 when (he was) king 做国王时。 when in position 恢复原位后。 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。
Example Sentences:
1.
His problem began when he was a child . 他的这个问题起始于孩提时代。
2.
When hard tactics failed , soft methods were used . 硬的不行来软的。
3.
I was just going to speak, when the bell rang . 我刚要讲，钟就响了。
4.
When can you take delivery of the car ? 你什么时候才能收到那辆汽车？
5.
When the boss falls from power , his lackeys disperse . 树倒猢狲散。
6.
Why use wood when you can use plastic ? 既然能用塑料，何必非用木料？
7.
Attendant : when did you bring it to us ? 服务员：你什么时候送来的？
8.
The film was already on when we arrived . 我们到时，电影已经开演了。
9.
When two tigers fight , one is sure to lose ... 两虎相争，必有一伤。
10.
When are you coming over to see us again ？ 你什么时候再来看我们呢？
