主谓

该句型的谓语动词是不及物动词（intransitive verb），所表示的动作没有作用对象，其本身意思完整，其后不需带宾语。尽管这个句型里没有宾语，但是在谓语动词后面往往会接状语，用来修饰谓语动词，比如表示动作发生的地点等。
	
简单句变长难句
This trend began during the Second World War. 
 该句的主语是this trend，谓语began是一个不及物动词，后边没有带宾语。介词短语during the Second World War作时间状语。 
This trend began during the Second World War, when several governments came to this conclusion. 
这里加了一个定语从句when several governments came to the conclusion，来修饰时间Second World War。这个定语从句是一个“主语＋谓语＋宾语”的句型，主语是several governments，谓语是短语动词came to，宾语是the conclusion。
This trend began during the Second World War, when several governments came to the conclusion that the specific demands cannot generally be foreseen in detail. 
 这里添加了一个同位语从句that the specific demands cannot generally be foreseen in detail，补充说明conclusion。这个同位语从句也是一个“主语＋谓语”的句型，这里的主语是the specific demands，谓语是一个被动结构cannot generally be foreseen，介词短语in detail作状语。
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. 
这里添加了一个定语从句that a government wants to make of its scientific establishment，来修饰demands。这个定语从句是一个“主语＋谓语＋宾语”的句型，主语是a government，谓语是wants，宾语是to make of its scientific establishment。很多读者也许看不出这里that作定语从句的何种成分。其实，这里的that指代先行词demands，在定语从句中作谓语make的宾语，从而构成一个make demands of的搭配，表示“对……提出要求”。很
 综上所述，上面这个复杂的句子其实是由四个简单句复合而成的，即有两个“主语＋谓语”结构的句子：this trend began during the Second World War和the specific demands cannot generally be foreseen in detail，还有两个“主语＋谓语＋宾语”结构的句子：several governments came to the conclusion和a government wants to make of its scientific establishment。