只能用 It 的.

如果你用what 当主语从句的引导词.即,what had never occurred to me是主语,那么它的谓语动词哪去了?你说呢?

希望能够帮助到你,祝你学习愉快!那么，如果改成主语从句，怎么改呢？What had never occurred to me was that he should have some deep personal objection.谓语动词是was.整个句子属于： S+V+P，即：主系表结构。