条件二：从句部分缺少状语。

The time when【you first met Nelson Mandela】 was a very difficult period of your life.

先行词 主 + 谓+ 宾（缺少状语）

（表时间）

分析并完成下列句子,体会关系副词的用法：

1. Mary Brown moved to a place _______she was close to the sea, so she could go swimming every day.

2. That was the reason _______I had to go to hospital.

3. Harvard is a world-famous university where/from which Wang An got his doctor's degree.

4. In 1951 Dr Wang founded his own company where/ in which computers were made.

5. Dr Wang died in 1990 when IT was developing rapidly all over the world.

二．"介词+关系代词"引导定语从句的用法。

【关键点】关系代词whom, which前介词的选择由先行词的习惯搭配或后半句动词的搭配而决定。

1. The speed at which light travels is 300000km per second.(由先