Exercise 11.3 The most important data-based evidence for movement in relative clauses with zero relative pronouns is that the island-constraints hold in just the same way for them as for relative clauses with overt relative pronouns. If the island constraints are constraints on movement, then something must be moving in the zero-relative pronoun case. Because of this parallelism, all modern theories of syntax treat the zero case as structurally identical to the overt relative pronoun case.

An added conceptual advantage of the movement analysis of the zero case is that it allows a unified treatment of all relative clauses, treating them like the other movement constructions, wh- questions and topicalizations.