一个的语法问题：关于主系表结构的例句：Iwasscaredthathelefthomeandwouldn'tcomebackagain.我的问题是：Iwasscared是主系表结构,那么后面that的那句是什么成分.我只知道有主系表结构,另外还

Question

一个的语法问题：关于主系表结构的
例句：
I was scared that he left home and wouldn't come back again.
我的问题是：I was scared 是主系表结构,那么后面that的那句是什么成分.我只知道有主系表结构,另外还见过主系表+状语的句子结构,但是that引导的那部分到底在句中做什么成分,我想知道这个句子的语法结构是怎样的.自下自己分析that引导的那个从句肯定不是补语,同位语肯定也不是,主系表后+that从句这个结构到底是什么语法现象,看了几本语法书均没有提到过这种情况.例句肯定是对的,是牛津第四版上的.

Answer 1

这是名词性that-分句作形容词补足成分,“形容词+that-分句”构成形容词词组作主语补语（即表语）.这种结构的主语一般都是人称主语,所用的形容词一般都是表示思想状况或感情色彩的形容词.例如：
I'm certain (that) I'll get there in time.
I'm afraid (that) I can't promise you anything.
She is convinced (that) he is honest.
He is positive (that) that's the man he saw yesterday.
We are anxious that everything should go smoothly.
They were rather disappointed that you could not come last week.
I'm a bit worried that she will not be able to make it.
They are glad that you have succeeded in your plans.
——引自章振邦主编、上海外语教育出版社1997《新编英语语法（第三版）》