They didn't get to the railway station on time,____ we hadn't expected.

问题描述:

They didn't get to the railway station on time,____ we hadn't expected.
as 还是which?
为什么选as/which,不选which/as?

我感觉选 which,定语从句
选as 语法没什么错,不过翻译过来看 "正如我们没想到的"..有人这么说话么...
如果是 as we expected 就可以