关系副词可以用介词加关系代词代替吗最好举一些例子

when（= at, on, in, during which)
where（ = in, at which)
why（for which)

how（in which)
He came at a time when (at which) we were badly in need of help. 他在我们急需人帮忙的时候来到了。
The school where (in which) I work is not far from here. 我工作的那个学校离这儿不远。
Is this the place where (at which) that traffic accident occurred? 这就是那个交通事故发生的地方吗？
He didn’t give the reason why (for which) he was absent yesterday. 他没有提到他昨天缺席的理由。
The reason why (for which) he missed the bus was that he got up late. 他没有赶上车的原因是他起床晚了。
We admired him for the way (in which/how) he faces his difficulties. （在现代英语中how较少用）我们佩服他克服困难的方法。