not only had the poor man been arrested.为什么主语要放到had been 的中间?

not only had the poor man been arrested.为什么主语要放到had been 的中间?
not only had the poor man been arrested.为什么主语要放到had been 的中间?

not only had the poor man been arrested.为什么主语要放到had been 的中间?
not 是否定副词,还有一些其他否定副词如never,hardly,rarely,no等位于句首时,句子都要部分倒装,即把助动词,情态动词或be动词放在主语之前,这句中had 是助动词,提前到主语的前面,构成部分倒装的形式

不是主语放到had been 的中间了，而是had提前了，这是一个倒桩，本来语序是the poor man had been arrested

not only 放句首要部分倒装，所谓部分倒装就是一部分谓语在前一部分在后，主语就夹中间了