托福TPO27 Reading2的一个句子。some overgrown with coral—that originated from activity at points in the interior of the Pacific Plate that forms the Pacific seafloor.第二个that引导的定语从句的先行词是points，还是Pacific Plate，还是activity
some overgrown with coral—that originated from activity at points in the interior of the Pacific Plate that forms the Pacific seafloor.
forms 是动词单三形式，它的先行词肯定是单数，排除 points。
太平洋版块 the Pacific Plate 是一个地区定义， 没办法形成太平洋海底。
activity 是抽象名词，指“活跃情况”，可以反映出太平洋海底的特点。（form 除去“形成” 的意思外，可以引申为“体现/反映...特点”）
