高考英语定语从句的写法如下：

确定先行词

先行词是被定语从句修饰的名词或代词。

选择关系词

关系词分为关系代词（that、which、who、whom、whose）和关系副词（when、where、why）。

关系代词在从句中充当主语、宾语或定语。

构建从句

在先行词后加上逗号（如果是非限制性定语从句），或者直接连接从句。

使用关系词引导从句，并确保关系词在从句中正确充当成分。

注意关系词的省略

在某些情况下，关系代词可以省略，例如：

The book thatI bought yesterday is interesting. [省略了that]

The book whichI bought yesterday is interesting. [which可以省略]

使用介词+关系代词

介词可以与关系代词一起使用，构成介词短语，修饰先行词。例如：

The book in whichI found many interesting stories was borrowed from the library. [in which]

示例

完整形式

The book that I bought yesterday is interesting. [that引导定语从句，修饰book]

省略形式

The book I bought yesterday is interesting. [省略了that]

介词+关系代词

The book in which I found many interesting stories was borrowed from the library. [in which引导定语从句，修饰book]

练习

1. The girl ______ I met at the party is my sister. [who引导定语从句，修饰girl]

2. The house ______ we lived in for ten years is now empty. [where引导定语从句，修饰house]

3. The reason ______ he was late is that he missed the bus. [why引导定语从句，修饰reason]

通过以上步骤和示例，你可以更好地理解和掌握高考英语定语从句的写法。多读、多练，结合实际语境进行学习，能够有效提高你的英语水平。