定语从句概述
定语从句是英语中非常重要的一种复合句，由一个先行词和一个在从句中修饰这个先行词的关系代词或关系副词组成。定语从句通常用于描述或修饰先行词，使句子更加清晰、准确、生动、有趣。学会如何合并定语从句不仅可以提高写作的熟练度，还可以使文章更加连贯有序，读者阅读起来也更加流畅。
合并两个定语从句
在英语写作中，有时候我们需要合并两个定语从句。这样做的好处是可以使文章更加简洁明了，读者也可以更加方便地理解。例如：
原句：I visited the museum which has a lot of famous paintings. The museum is located in the city center.
合并后：I visited the museum which has a lot of famous paintings and is located in the city center.
可以看到，在合并后的句子中，第一个定语从句 "which has a lot of famous paintings" 和第二个定语从句 "is located in the city center" 被合并成为了一个整体，组成了一个更加简洁明了的句子。
合并带有关系代词who/whom/whose的定语从句
合并带有关系代词who/whom/whose的定语从句时，需要注意一些细节。例如：
原句：The boy who is sitting next to me is my brother. The boy introduced me to his friend.
合并后：The boy who is sitting next to me and introduced me to his friend is my brother.
需要注意的是，合并后的句子中，被合并的两个定语从句之间需要添加逗号，并将第一个定语从句中的关系代词who改为and。
合并带有关系副词的定语从句
相比于带有关系代词的定语从句，合并带有关系副词的定语从句相对简单。例如：
原句：The house where I grew up is near the park. The house was built in the 19th century.
合并后：The house where I grew up and was built in the 19th century is near the park.
可以看到，通过将两个定语从句合并为一个，不仅能使文章更加简洁，还可以使句子结构更加清晰。
结尾
合并定语从句是英语写作中非常重要的一种技巧，可以使文章更加简洁明了，读者也可以更加方便地阅读。在使用定语从句时，需要注意语法和逻辑的准确性，合理运用句式和词汇，才能写出优美、流畅的文章。