该内容是考试会涉及到的知识点，北京张博士医考中心搜集整理，请参考。

　　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形式主语句型，well read about the period 做后置定语修饰满意people， about the period 介词短语跟动词短语后，可在翻译时调整语序 about the period well read. between tho张博士医考网http://www.guojiayikao.comse who made codes and those who broke them 做后置定语修饰 a battle。翻译时两后置定语均需调至所修饰的名词前。Those who made codes and those who broke them 两定语从句前置翻译即可。

　　参考译文： 即使是对许多这段时期历史了如指掌的人来说，他们也不知道这也是一场创造密码的人和破解密码的人之间的战役。

　　「张博士医考www.guojiayikao.com整理，如有转载，请注明出处」