主语一般有人称代词、指示代词、不定代词、关系代词、名词、形容词。
指示代词:this,that,those,these。
不定代词:one,each,some,any,something,everything,nothing,anything。
关系代词:which,that,who。
名词:room,fire,steel,work,happiness。
形容词:my,your,his,her,its,our,their。
句子作主语
that引导的从句,无意义,不担当句子成分,不省略。
It +v+ that从句。
It +系动词+表语+that从句。
It is strange that he didn't come here yesterday.奇怪的是,昨天他没来这里。当形容词为important necessary strange /that should +动词原形It is strange that he should(表示吃惊)pass the exam.奇怪的是,他可以通过考试。