题干分析：教授讲的主要内容。

原文定位：

Okay, last time we talked about something that rose to popularity in the United States in the late 1880s a form of entertainment known as vaudeville.…… Vaudeville would remain popular until the 1930s after which it was replaced by the new entertainment of choice, moving pictures. But the relationship between vaudeville and movies is not simply about competition or the replacement of the old by the new.

选项分析：考察转折考点，开头讲到上节课主要讲了歌舞杂耍表演和它的崛起，引出歌舞杂耍表演逐渐消亡，被电影取代，但又指出这并非只是新旧事物之间的竞争和取代关系，接下来的全文都在讲歌舞杂耍表演和电影我中有你，你中有我的关系，可知应选D选项。