what the most impotant things is that what the most impotant

what the most impotant things is that what the most impotant is that 这两个句子说法都对吗
what i want to emphasize here is that XXX
以上的句子 这些 what 是个什么句子 what 做什么成分 我只知道 that 前面的部分在这里是作主语 ,可以给我 一点别的例子吗

what i want to emphasize here is that XXX
what 引导的是主语从句,what是引导词--连接代词,在主语从句中作宾语,该主语从句的原型你可以理解为“I want to emphasize …….”,因为这是个完整的句子,无法在一个复杂的句中作主语,故把“……”部分用what替代,放在句首,构成主语从句,what在主语从句中可译为“…所…”“什么所如何的”,如这里翻译为“我所想强调的”.
主语从句可以由下列连词,连接代词和连接副词引导,且不能省略.
连词 that,whether
连接代词 what,whatever,who,whoever等
连接副词 when,where,how,why
1.that 和whether在主语从句作用中只是引导主语从句,在从句中不充当成分,不能省略.
如：That the earth is round is true.
Whether he will come is doubtful.
2.连接代词who,which和连接副词when,where,how,why都可以引导主语从句,在从句中作主语、宾语和状语,不能省略.由它们引导的主语从句,也可以用形式主语it引导.
如：Who let out the news remains unknown.=it remained unknown who let out the news.
谁走漏了消息仍然不得而知.
3.关系代词what,whatever,who,whoever在主语从句中担当成分,不能省略.此类主语从句不可以用形式主语it引导.
如：What he said at the meeting is important.(what在主语从句中作宾语,不可省略)
Whenever the school sports will be held is not known yet.(Whenever在主语从句中作状语,不能省略)
“is that XXX”是系表结构共同构成谓语部分,that引导表语从句,如：My idea is that we all go to school on foot.
再问： what the most impotant things is that what the most impotant is that 按照你这样说那么第一个句子就不正确咯？ 这两个句子 表述都是正确的吗？ 帮我分析一下句子成分吧 谢谢
再答： 可以直接说The most important thing is (that I love her), 为什么要加what呢？如果非要用what引导主语从句，be动词要提到the most important thing前，后面再加谓语，如：What is the important thing depends on your choice. What is the important thing is that you love her.(实际上此句语法上是不错的，但就很罗嗦了，不符合语言简练的规则)