What 引导主语从句时在从句中充当句子成分,如主语．宾语．表语,而that 则不然.请问例子?两个都要.例子尽量多,最好还有点解释

What surprised me most was that he had been married.（what在从句中作主语）What you told me this morning is unbelievable.(what 在从句中作宾语）What his phone number is is still unknown to me.（what在从...