It was October _when__ the People’s Republic\x0b of China was founded

问题描述:

It was October _when__ the People’s Republic\x0b of China was founded
It was October __when_ the People’s Republic\x0b of China was founded
It was in October__that_ the People’s Republic\x0b of China was founded.
为什么

第一个句子:It was October when ...这里的 when 引导定语从句,修饰 October,全句直译是:那是*成立的十月.(当然,此句需要意译才会更通顺).
第二个句子:It was in October that ...是一个 it was...that 的强调句型,它的陈述句是 The People's * was founded in October. 改成强调句型后不能漏掉陈述句中的任何一个成分,因此需要完整的状语 in October.