Since Ross (1967), it has been observed that there are configurations from which otherwise unbounded movement operations cannot occur, and they are called islands. Ellipsis and resumption are known to have a peculiar property to 'repair' island violations. Each chapter of this thesis discusses a case of ellipsis/resumption to examine in what cases movement out of an island becomes licit by those strategies. Chapter 2 discusses the elliptical construction called sluicing, and argues for the PF-deletion analysis of sluicing (Merchant 2001, originated from Ross 1969). I will show that ECP violations made by adjunct sluicing cannot be repaired by sluicing, unlike island violations. I will thus argue that island violations are PF-violations while ECP violations are LF violations, and that PF-deletion ameliorates only PF-deletion. Chapter 3 examines properties of stripping and argues that stripping is derived by focus movement followed by PF-deletion. I try to attribute the lack of island repair under ellipsis in stripping to the fact that focus movement is not usually overt in English. Covert movement is derived by a weak feature (Chomsky 1995), but when a focused material is included in the PF-deletion site, it undergoes last resort PF-movement to satisfy the recoverability of deletion. I claim that this PF-movement is incompatible with island-repair, speculating that island violations are ameliorated at spell-out, and post-spell-out movement is 'too late' to be repaired. Chapter 4 reviews properties of Japanese sluicing, and introduces Hiraiwa and Ishihara's (2002) analysis where Japanese sluicing is derived from what they call "no da" in-situ focus construction. Under this analysis, the sluiced wh-phrase undergoes focus movement, followed by clausal deletion. I adopt the analysis of stripping to Japanese sluicing, claiming that this is another instance of the last resort focus movement at PF, which cannot ameliorate island violations. Chapter 5 discusses properties of Left Node Raising (LNR) in Japanese. Based on the fact that simple LNR shows properties distinct from Null Object Construction (NOC), I claim that LNR involves ATB-movement rather than NOC. However, the second gap of LNR behaves like a pronoun only when included inside an island. I claim that this is an instance of null resumptive pronoun.