对于雅思写作而言，长难句一直是困扰不少考生备考过程中的提分障碍。其实，长难句无非是英语不同于汉语的一种信息组成方式的体现：英语更倾向于把很多信息集中到一个句子中，形成各种从句;汉语则更喜欢以短句为主，来表达复杂信息。明白这个规律之后，笔者将为各位烤鸭们剖析雅思写作高频复杂句的使用技能。
　　定语从句
　　纵观剑4至剑10的所有考官范文，定语从句乃是当之无愧高频句，现摘取如下较典型的例句与读者共同探讨：This has been driven by technological and scientific breakthroughs that are changing the whole way we view the world on an almost daily basis.句中，that 引导的定语从句：that are changing the whole way we view the world on an almost daily basis. 是对先行词technological and scientific breakthroughs 的限定说明，它不影响主句：This has been driven by technological and scientific breakthroughs. 的语法结构。因此，我们的出结论：定语从句的功能是对句中某个名词作限定说明，使用方法就是在名词后+that/which(先行词为事物)或who(先行词为人)并且把这些引导词当成主语，接着补充成一个句子就行啦。
　　状语从句
　　再看看同样使用频率较高的状语从句：For example, if sufficient sky trains and underground train systems were built and effectively maintained in our major cities, then traffic on the roads would be dramatically reduced.句中，if 引导的是条件状语从句：if sufficient sky trains and underground train systems were built and effectively maintained in our major cities. 主句一般而言表示基于此条件的结果。我们试着来总结一下它的使用公式：if+句子(条件)+ then+句子(结果)。需要注意的是由于是虚拟条件，if 引导的条件从句用一般过去时，主句用虚拟语气较为常见。(具体请参照例句理解)
　　宾语、表语从句
　　宾语从句、表语从句也很常见：They may think that it is better to continue in a particular job, or to do something completely different from a university course.句中，that 引导的从句：that it is better to continue in a particular job, or to do something completely different from a university course. 作think 的宾语。That 本身在从句中不做任何成分。我们来探讨宾语从句的使用规律：主语+谓语+that+完整句子。就构成了一个宾语从句。按此规律，我们来看看表语从句：The obvious argument in its favour is that young children pick up languages much more easily than teenagers.句中，that 引导的表语从句：that young children pick up languages much more easily than teenagers. 作系动词 is 的表语。使用方法不再赘述。
　　最后，同位语从句
　　笔者给大家看看同位语从句：Obviously, education systems are based on the belief that all children can effectively be taught to acquire different skills, including those associated with sport, art or music.句中，that引导的同位语从句：that all children can effectively be taught to acquire different skills, including those associated with sport, art or music. 是对先行词belief的补充说明。其用法为：在句中需要补充说明的名词后+that +句子。注意，同位语从句的引导词一般是that，并且不在从句中作成分，定语从句则有多个引导词，且一般在从句中做成分。