2.4 Corpus-driven Studies of Phraseology

In the past two decades or so，the study of phraseology has come into its own，and its recent rise to a prominent position in linguistic studies has been characterized by many different perspectives and foci of interest.The study of phraseology has traditionally been driven by pre-selected theories with a top-down approach.The main preoccupation is to find linguistic criteria for distinguishing one type of phraseological unit from another and especially for distinguishing the most variable and transparent multiword units from free combinations.The present study adopts a bottom-up approach which is basically corpus-driven（e.g.Sinclair 1987）and frequency-based.For a detailed distinction between two approaches to phraseology，see Cowie（1998），Granger&Paquot（2008），and Wei（2011）.