This thesis takes as its starting point the proposal in Kayne (1994) that all syntactic structures are underlyingly spec-head-complement, and that they are right-branching. I will investigate this proposal taking data from English degree constructions, namely result clauses and comparatives. A comparison will be made between these constructions and English VPs, on which the majority of the phrase structure debate in the literature has been based. The evidence for left-branching and for right-branching in VPs will be considered, and similar evidence sought for degree constructions. We will see that VPs have a mostly right-branching structure, although left-branching structures are required in restricted circumstances. Also reason and manner adjuncts are argued to be right-adjoined to the VP node, a conclusion that is re-inforced by considering the constituency of VP adjuncts and some PP sequences noted by Jackendoff (1973). In degree constructions too, we argue that both left-branching and right-branching structures are necessary. My conclusion will be that Kayne's proposal is too strong, even though it is ideal from the perspective of a minimalist approach to syntax.