疑问代词
疑问代词有who，whom，whose，what和which等。疑问代词用于特殊疑
问句中，一般都放在句首，并在句子中作为某一句子成分。例如：
Who is going to come here tomorrow? (作主语)
IX关系代词
关系代词是一种引导从句并起连接主句和从句作用的代词。关系代词有 who, whose, whom, that, which. 它们在句中可用作主语,表语,宾语,定语. 在主句中,它们还代表着从句所修饰的那个名词或代词。例如：
I hate people who talk much but do little.
X it的用法小结
1指代上文提到的名词 There is a pen on the desk. It’s mine
2表示时间，天气，距离等 It’s raining so heavily.
3做句子的形式主语 It took the villagers ten years to build that road.
4做句子的形式宾语 They found it hard to learn English well.
We really think it crazy that some people swim in rivers in winter.
Her illness made it a problem to have sports.
5强调句中
It is….that/who It’s the bad weather that made us lose our way.