Contents 丛书序i 前言iii Chapter One Introduction1 1.1 Rationale for the Present Research5 1.2 State of the Art and Problems9 1.2.1 Previous Researches on Diachronic Evolution of BUGUO and XKAN9 1.2.2 Previous Researches on Synchronic Aspects of BUGUO and XKAN13 1.2.3 Why Diachronic?16 1.2.4 Interim Summary22 1.3 Diachronic Work Relevant to This Book24 1.3.1 Grammaticalization24 1.3.2 Pragmaticalization31 1.3.3 Models of Semantic Change36