only 引导的部分倒装

问题描述:

only 引导的部分倒装
Only when the war was over was he able to return home.这句是部分倒装吧?那为什么要把was 倒装了?后面的句子 可以还原成 he is able to return home.那这个句子里谓语在哪里?是be able to return么

He was able to return home only when the war was over .
放后面就不倒装,倒装的是主句,动词提前,这里谓语动词是was.