特殊疑问句what caused him to be sad?

问题描述:

特殊疑问句what caused him to be sad?
为什么不说 what did cause him to be sad?
还有happen这个词
what happened to sb?按语法来说应该是what did happen to sb?
这不是个定语从句;2楼不明白什么意思;
最初语法不是说特殊疑问句=特殊疑问词+一般疑问句吗
更疑惑了 cause 这个词是个及物动词啊

当特殊疑问词在句中作主语时,不用助动词,疑问词后直接加谓语动词.