Is the world a more complicated and dangerous place than it was when previous generations were allowed to wander about unsupervised?
请教一下，在这个句子中，when previous....属于什么从句？than it was又该如何解释呢？谢谢了

一个是比较 一个是比较里的世界状语

时间

这个than 在搞鬼。
加个what,写成 than what It was when ...就容易理了