THAT 这里的词性并且,THAT 在这里可以省略吗?he admits that he is wrong

that 是连接词,用来陈述一个存在的事实,用来引导名词从句的.
宾语从句：She said （thats he would come) .她说她要来.
主语从句：It so happens （that I know the man）.碰巧我认识那个人.（it 是形式主语,指代后面that引导的主语从句）
表语从句：The trouble is （that we are short of money）.困难是我们资金短缺.
同位语从句：The trouble （that we can't finish the work on time） is known to us all.我们不能按时完成这件工作的困难是众所周知的.
二、that 并没有实际上的含义,只是个语法符号,表明它后面跟的是名词从句.that 引导宾语从句时可以省略,表语从句有时候也可以省略,但是引导主语从句个同位语从句则不可以省略,如：
He admits that he is wrong 也可以写成 he admits he is wrong
She said that she would come.也可以写成 She said she would come