46.It was also, and this is unknown even to many people well read about the period, a battle between those who made codes and those who broke them.
解析：it was unknown to may people 是it情势主语句型，well read about the period 做后置定语润饰得意people， about the period 介词短语跟动
词短语后，可在翻译时调解语序 about the period well read. between those who made codes and those who broke them 做后置定语润饰 a battle。翻译时两后置定语均需调至所润饰的名词前。Those who made codes and those who broke them 两定语从句前置翻译便可。
47.It listed many documents in code that had been captured from the French army of Spain, and whose secrets had been revealed by the work of one George Scovell, an officer in
解析：这个句子有两个由and并列的定语从句，别离由that和whose指导，in code 介词短语做后置定语润饰documents,同时它也是一个距离布局，把that指导的定语从句与先行词documents间离隔来，翻译时可前置，that had been captured…定语从句顺译便可，that可以译为它们，from the French army of Spain前置翻译放had been captured前翻译。 An officer in British headquarters可前置放George Scovell前便可.
48.he could not analyze carefully what this obscure officer may or may not have contributed to that great struggle between nations or indeed tell us anything much about the man himself.
解析：句子第二个or并列的是could not analyze…和indeed tell us…, 是以indeed后也是否认寄义，may or may not直接译成是不是便可，between nations 做后置定语，可微调至that great nation前。 Obscure 原意是艰涩难明的，润饰officer指使人捉摸不透的。
49.There may have been many spies and intelligence officers during the Napoleonic Wars, but it is usually extremely difficult to find the material they actually provided or worked on.
解析： there may 时候状语during…提至句首，the material they actually provided or worked on包括了一个省略了隶属连词的定从。They actually provided or…可提早到material前前置翻译。
50.Just as the code breaking has its wider relevance in the struggle for Spain, so his attempts to make his way up the promotion ladder speak volumes about British society.
解析：just as…, so 正如……也。In the struggle for Spain 做状语，在翻译时可放has its…前翻译，to make his way up the promotion ladder 做后置定语润饰attempts. Speak volumes 说了大量（供给了很多信息）。