你给的句子有问题,The subject of written research the writer first thought was（这里的was是多余的） directly connected with his study was thrift.句子的主干是：The subject was thrift.主题是节俭.其中The ...如果有was，那么从句为the writer first thought（the subject） was directly connected with his study，是不是也说得通？（省略的关系代词做 thought的宾语从句的主语）这好像太绕了……