关于此问题，之前，曹老师曾做过很好的解答。见：

http://ask.yygrammar.com/q-28798.html

类似用法，我再补充几句：

1. His mother’s death when he was ten had a very great effect on him. 

他10岁时母亲的过世对他的影响很大。

2. She often recalls the time before she married him, and it was so wonderful.

她经常回忆起嫁给他之前的那段时间，那是多么美好啊。

3. Every hour since I came has been most enjoyable.

我来之后的每一个小时都非常好玩。

网友总能提出精彩的问题，专家总能给出精彩的解答，有幸在答疑网学习英语真好！

这个问题前几天刚有人提过。有点儿像状语从句，这里是个用作定语从句，修饰的是照片。

We are interested to see photos of my mother when she was young.

参考译文：当我妈妈年轻的时候，我们都很有兴趣看她的照片。

when she was young修饰主句谓语动词are interested,作主句时间状语。