while和when什么情况下可以互换

while和when什么情况下可以互换
表示“当......的时候”讲，能用while的地方都可以用when吗？

While 后面跟的从句里的动作是正在进行时 he comes home while his mother is cooking.when就不是了 he comes home when his mother cooks.
再问： 非常感谢哟！想再请问下when/while she was visiting the museum, an alien came in. 这个位置互换的理由是什么呢
再答： 当从句的谓语是表动作的延续性动词时，when, while才有可能互相替代。如： While / When we were still laughing, the teacher came in.正当我们仍在大声嬉笑时，老师进来了。