What was real to him were the details of his life.

不是把整个主语从句当一个整体,谓语用单数吗?为何这个句子中用复数呢?

只说what从句做主语的状况：

结论：单数、复数都对. 但到现在，用单数的还是普通一些：

说用复数可以，是“翻转派”，即：

What was real to him were the details of his life.

----the details of his lifewerewhat was real to him.

仿佛是非常有道理，但反对的人觉得，如此实质是改变了原始结构，不算。

所以用单数还是复数，这就看个人的偏好了。