it was obvious that he was very embarrassed 名词从句部分我不理解

it was obvious that he was very embarrassed 名词从句部分我不理解
that he was very embarrassed 首先这句话作名词的意思,我不理解,用中文翻译过来怎么都不像是名词.他因此很尴尬,你们觉得像名词吗?还有Was 后面的动词按理说应该是原形,Embarrassed 是过去式还是过去分词,如果是过去分词,那么这个was embarrassed 他为此很尴尬!是这样吗

it(形式主语） was （系动词）obvious（表语） that he was very embarrassed （名词性从句做主语---主语从句）
1.名词性从句,是指其功能相当于名词,名词能做主语,它如果可以,不就相当于名词吗?不要狭义地和表示单一意思的名词来比.
2.was embarrassed（形容词,尴尬的） 是【系表结构】 意即：很尴尬