That's just as it should be.as可以引导名词从句吗,在这里做什么成分?

just as可以引导名词性从句,本句就是它引导的表语从句,as本身在表语从句中做表语.整体看本句是主系表结构,that是主语,is是系动词,just as引导表语从句,从句的主语是it,should be是系动词,而表语就是as了,just做状语,其实它仅起到强调作用.That's just as it should be.句意：理应如此.直译：那就是它应该是的样子.
另外说一下,just as 有以下的意思和用法：
1. 正如
The house was just as she had imagined it.\x09（引导表语从句）
这房子正是她所想象的.
2. 当,在.的时候,正在
A visitor arrived just as we were setting out for the airport.\x09（引导时间状语从句）
我们正要前往机场时来了一位客人.
3.就按照
Do as what I said just now.就按照我刚才说的做.（引导方式状语从句）
just和as通常一起出现,其实这就跟as单独的用法一样,just仅起到强调作用.
希望可以帮助到你,不明白可继续追问.