In the absence of a stranded auxiliary or modal, VP-topicalization in most Germanic languages gives rise to the presence of a dummy verb meaning ‘do’. Cross-linguistically, this is a rather uncommon strategy as comparable VP-fronting constructions in other languages, e.g. Hebrew, Polish, and Portuguese, among many others, exhibit verb doubling. A comparison of several recent approaches to verb doubling in VP-fronting reveals that it is the consequence of VP-evacuating head movement of the verb to some higher functional head, which saves the (low copy of the) verb from undergoing copy deletion as part of the low VP copy in the VP-topicalization dependency. Given that almost all Germanic languages have such V-salvaging head movement, namely V-to-C movement, but do not show verb doubling, this paper suggests that V-raising is exceptionally impossible in VP-topicalization clauses and addresses the question of why it is blocked. After discussing and rejecting some conceivable explanations for the lack of verb doubling, I propose that the blocking effect arises from a bleeding interaction between V-to-C movement and VP-to-SpecCP movement. As both operations are triggered by the same head, i.e. C, the VP is always encountered first by a downward search algorithm. Movement of VP then freezes it and its lower copies for subextraction precluding subsequent V-raising. Crucially, this implies that there is no V-to-T raising in most Germanic languages. V2 languages with V-to-T raising, e.g. Yiddish, are correctly predicted to not exhibit the blocking effect.

在没有搁浅助词或情态动词的情况下，大多数日耳曼语言中的 VP 主题化都会出现一个表示“do”的虚拟动词。从跨语言角度来看，这是一种相当罕见的策略，因为其他语言（例如希伯来语、波兰语和葡萄牙语等）中类似的 VP 前置结构都表现出动词双重。对 VP-fronting 中动词双倍的几种最新方法的比较表明，这是动词 VP 疏散头部移动到某些更高功能头部的结果，这使动词（的低副本）免于作为一部分进行副本删除VP 主题化依赖性中的低 VP 副本。鉴于几乎所有日耳曼语言都有这种 V 型抢救性头部运动，即 V 到 C 运动，但没有表现出动词重合，本文认为 V 型提升在 VP 主题化从句中是极其不可能的，并解决了为什么的问题它被阻止了。在讨论并拒绝了一些对缺乏动词重复的可能解释之后，我提出阻塞效应是由 V 到 C 运动和 VP 到 SpecCP 运动之间的出血相互作用引起的。由于两个操作均由同一头（即 C）触发，因此向下搜索算法总是首先遇到 VP。然后 VP 的运动将其及其较低的副本冻结以进行子提取，从而阻止随后的 V 升高。至关重要的是，这意味着大多数日耳曼语言中没有 V 到 T 的提升。具有 V 到 T 提升的 V2 语言（例如意第绪语）被正确预测为不会表现出阻塞效应。