长难句

The supposed importance of influentials derives from a plausible-sounding but largely untested theory called the “two step flow of communication”: Information flows from the media to the influentials and from them to everyone else. (2010 Text3)

难句分析

分句1

The supposed importance of influentials derives from a plausible-sounding but largely untested theory called the “two step flow of communication”

主语 谓语 宾语 同位语

分句2

Information flows from the media to the influentials and from them to everyone else

主语 谓语 状语

本句为冒号连接的两个简单句，冒号后面的句子是对“two step flow of communication”的解释说明。分句1中主语的中心词是importance，宾语的中心词为theory，用并列连词but连接两个形容词修饰theory，called the “two step flow of communication”过去分词短语解释说明这个理论是什么。分句2再具体详述信息的“两级”流动。

参考译文

所谓有影响力人士的重要性源于一个听上去言之有理，但在很大程度上未经证实的名为“两级流动传播”的理论：信息从媒体流向有影响力人士，再从他们流向其他所有人。