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，结合考研英语阅读或翻译真题中的长难句进行实战演练一下。

1、{C}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

①找谓语动词(began, came, wants, cannot be foreseen);

②找连词(when, that, that)

③前面没有从属连词的动词即为主句的谓语动词

④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。