ABSTRACT: The paper explores the role of the copula 是 si7 in the interpretation of the focus structure in early Southern Min playscripts. I examine the configuration of 是 si7 with respect to a range of functional/lexical categories such as kinds of adverbs, types of modals, voice (featuring causativity and passitivity), aspect, and negation as well as verb and noun phrases. I also put forward tree structures showing how focus vis-à-vis topic in cleft and pseudo-cleft clauses with 是 si7 as the pivot are derived. In a nutshell, the syntactic position of 是 si7 is versatile and yet constrained. There is an asymmetry of the distribution of subject and object focusing with respect to the position of the copula 是 si7 . I posit with Rizzi (2013) that the focus feature in the FocP triggers merging the focus constituent to the head Foc in FocP in CP. Apart from bearing the assertive force in the clause typing, the copula 是 si7 plays a supporting role of scoping over the focus constituent. I capture the syntactic behavior of the copula 是 si7 by construing it as an indispensable pivot in the derivation of focus structure. o put forward tree structures showing how focus vis 摘要: 本文探讨早期闽南戏文中系词"是" 在焦点结构中所扮演的角色。从和各类状语、情态词、语式(表被动或致使)、体貌、否定和动词、名词组成的相对位置可以确定"是"的结构特性。文中呈现分裂句及准分裂句中焦点相对于话题的树形图,其中"是"为轴心,约言之,"是"的句法位置多元而有限制。以系词"是"的位置为参照,可以看出主语焦点和宾语焦点在结构分布上有不对称的现象。以 Rizzi (2013)为依据本文假设焦点词组中的焦点征性触发焦点成分并入 CP 中的焦点中心语中,除了表示句式的论断语势外系词"是"还发挥辅助焦点成分的作用。总之,本文主张系词"是"是焦点结构中不可或缺的轴心,如此可以捕捉到"是"的句法行为。