题目内容：

the war broke out in the year _he and his brother were born in
A when B which
为什么不用WHEN呢
如果后面是were born 答案还是which

优质解答

which是关系代词,可以引导后面的定语从句,并在从句中作了介词in的宾语；而when是副词,不能做in的宾语
如果后面是were born 答案不是which；而是when