Preface 1 Overview 1.1 Introduction 1.2 Definitions 1.3 General information 2 Previous Literature 2.1 The semantics of the copula and its role in focus marking 2.1.1 Higgins, Richard. 1979. 2.1.2 Mikkelsen, Line. 2005, 2011. 2.1.3 The copula in the cleft constructions 2.2 Previous works on the cleft construction in Mandarin Chinese 2.2.1 Teng, Shou-Hsin. 1979. 2.2.2 Huang, C-T. James. 1982. 2.2.3 Zhu, Yao. 1996. 2.2.4 Li, N Charles & Thompson, Sandra. 1989. 2.2.5 Cheng, Lisa. 2008. 2.2.6 Hole, Daniel. 2011. 2.2.7 von Prince, Kilu. 2012. 2 Copula in Focus Constructions 2.2.8 Zhan, Fangqiong & Sun, Chaofen. 2013. 2.2.9 Other works 2.3 Grammaticalization of copulas in historical Chinese 2.3.1 The grammaticalization of the copula wei 2.3.2 The grammaticalization of the copula shi 2.3.3 The grammaticalization of the copula xi 2.3.4 Interim Summary 3 The copula wei（唯）in Pre-Classical Chinese 3.1 Overview 3.2 Wei's non-copular uses 3.3 The distribution of wei in copular clauses 3.4 The decline of wei's copular use 4 The copula shi（是）in Early Medieval Chinese 4.1 The reanalysis of shi into a copula 4.2 The distribution of shi in copular clauses 4.3 Shi in cleft constructions 5 The copula xi（系）in Late Medieval Chinese 5.1 The reanalysis of xi into a copula 5.2 The distribution of xi in copular clauses 5.3 Xi in cleft constructions 5.4 Modern day pattern 5.5 Summary 6 Conclusion Contents Sources