本文探討動詞組領域內論元出現及配置限制之現象。我們觀察的語料主要為主語倒置結構，且其中主語或賓語之移位均不為擴充投射原則 (EPP) 所驅使；進一步來說，我們探討許多倒裝結構中一項共有的特性，即若主語或賓語帶有不能詮釋的格位屬性，則其必須由動詞組內移出。本文認為此種論元外移現象可由語段無滲透條件 (PIC) 推導出，乃為此條件之必然結果。

This article investigates the placement restrictions on the number of arguments inside the verbal domain. The empirical basis consists of subject inversion cases where overt subject or object movement is not required for EPP-related reasons. Specifically, we look at a variety of inversion constructions where either the subject or the object with uninterpretable Case features must vacate the vP. I will show that the necessity of such argument externalization is a natural consequence of the Phase Impenetrability Condition (Chomsky 2000, 2001).