同位语的一般用法已为人们所熟知,但是,在阅读中我们有时还会遇到一种起同位语作用的外位成分。它的特点是:单独置于句子之外,构成外位(extraposition),句中由代词替代,两者复指同一对象。 The general usage of appositives is well known to people, but in reading we sometimes encounter an external component that acts as an appositive. It is characterized by: being placed out of a sentence alone, constituting an extraposition, being substituted by a pronoun, and both refer to the same object.