it seemed that everything went wrong this morning.that 引导什么从

表语从句
seem在这里可以看作系动词,看作 “主+系+表”结构.
再问： 我觉得也是表语从句，但是书上说that-clause is a nominal clause introduced by “that” and is used as the subject.意思是that 引导的从句做了主语。。。
再答： 没道理呀，肯定是表语从句。 例证： It seems that she has changed. 这是标准的表语从句呀。 如果非要认为是主语从句，那只能解释为：it 是形式主语，后面的从句是真正的主语，但我觉得讲不通。