如果按比较状语从句理解的话，是这样的: As （it）is true of any developed society （that a complex set of cultural signals, assumptions, and conventions underlies all social interrelationships,） in America a complex set of cultural signals, assumptions, and conventions underlies all social interrelationships. 在这里其实是陈述语序。有点儿复杂，所以首先应该接受这种通过来理解比较状语从句的方式。否则的话，按定语从句理解可能更方便一点。

As is true of any developed society, in America a complex set of cultural signals, assumptions, and conventions underlies all social interrelationships.

参考译文：正如与任何一个发达社会的情况一样，在美国，一套复杂的文化标志、假设以及风俗习惯都是构成整个社会的相互联系的基础。

以上为as引导的比较状语从句倒装结构。从句意思为“正如任何发达的社会一样”。

主句：a complex set of cultural signals, assumptions, and conventions underlies all social interrelationships.

(备注：还可以理解为as 引导非限制性定语从句，关系代词as并在定语从句作主语)

 A be true of B   意思为A 对B适用，A符合于B

 That might be true of somebody else but not of my Wang.  

但那只是另外那人的,却与我的毓芳无关.

This will very likely also be true of homosexual and bisexual relationships.  

接纳同性和双性性关系也极可能变为现实.

Hainan Airlines will be true of local government funding it?  

海航真能得到地方政府注资 吗 ?

And the same seems to be true of God.  

并且一样似乎上帝真.

May be true of us , beloved brothers and sisters!  

亲爱的弟兄姐妹,的确如此!

I accept that the romance may have gone out of the marriage, but surely this is true of many couples.

我同意婚姻里可能已经没有了浪漫这一说法，而且很多夫妻都的确如此。