考博英语长难句拆分要遵循这样的原则：把主句和从句拆分出来，把主干部分和修饰部分拆分出来。
但是遇到长难句时，具体要从哪些地方切入进行拆分呢?
考博英语长难句拆分信号：
1、标点符号：
比如，2个逗号形成插入语，破折号表示解释说明，分号相当于“and”表示并列;
2、连词：
并列句的并列连词and、or、but、yet、for等，从句的从属连词which、that、when、how、if等;
3、介词：
介词引导介词短语，介词短语在句子中可充当定语、状语等修饰成分;
4、不定式符号to：
不定式符号to引导不定式短语，在句子中除了可以充当主语、宾语、表语、补语等主干成分外，还可做定语、状语等修饰成分;
5、分词：
分词包括现在分词和过去分词，在句子中可充当定语和状语修饰成分。
下面我们就按照长难句拆分原则，依照这些拆分信号，结合考博英语阅读或翻译真题中的长难句进行实战演练一下吧!
1、This trend began during the Second World War, when several governments came to the conclusion that the specific demands that a government wants to make of its scientific establishment cannot generally be foreseen in detail.
(1)句子拆分
拆分点：从属连词、介词、标点符号
This trend began ∥during the Second World War, ∥ when several governments came to the conclusion ∥that the specific demands ∥that a government wants to make of its scientific establishment cannot generally be foreseen ∥in detail.
(2)句子结构
找谓语动词(began, came, wants, cannot be foreseen);
↓
找连词(when, that, that)
↓
前面没有从属连词的动词即为主句的谓语动词
↓
确定主从句
主句：This trend began during the Second World War ;
从句：定语从句when several governments came to the conclusion修饰the Second World War，本从句嵌套着一个二级从句即同位语从句that the specific demands cannot generally be foreseen in detail修饰conclusion和一个三级从句that引导的定语从句that a government wants to make of its scientific establishment修饰demands。
(3)解析
during the Second World War介词短语做状语;when several governments came to the conclusion that the specific demands that a government wants to make of its scientific establishment cannot generally be foreseen in detail 做定语修饰the Second World War ;that the specific demands cannot generally be foreseen in detail同位语从句修饰conclusion ;that a government wants to make of its scientific establishment修饰demands。
(4)本句的参考译文
这种趋势始于第二次世界大战期间，当时一些国家的政府得出结论：政府向科研机构提出的要求通常是无法详尽预见的。