本文針對現代漢語中判斷動詞"是"、焦点標記"是"和詞內成分"是"幷存的現象，從"是"是否發生詞匯化入手，重新分析了以往硏究中副詞"還是"的性質，認爲三種情況下的"還"、"是"共現不是副詞"還是"，而是詞組：(1)"是"爲判斷動詞，做謂語中心語時；(2)"是"爲其后體詞的 焦点標記時；(3)焦点標記"是"和句末語氣詞"的"共現時。在此基礎上再次明確了副詞"還是"的 義項，幷認爲只有表類同義的"還是"和表延續義的"還"在動詞和形容詞之前存在替換可能性， 幷從語素"是"的"主觀肯定義"出發，辨析了"還是"與"還"用法上的具體差異。

This paper aims at "是" coexisting as the judgment verb, focus sign and word-internal element in modern Chinese to reanalyze the nature of adverb "還是" in the previous studies based on whether "是" is lexicalized or not. It is concluded that three situations of the co-occurrence of "還" and "是" do not mean adverb "還是" but one phrase: 1) "是" is the judgment verb when it is used as predicate center; 2) "是" is focus marker when followed by nominals； 3) when "是" and "的" at the end of the sentence coexist. On the basis of this, meanings of adverb "還是" is reaffirmed in this paper. It is suggested that there exist substitution possibilities between verbs and adjectives when "還是" means continuity synonym and "還" refers to time continuation. Furthermore, the usage of adverb "還是" and "是" is discriminated based on subjective confirmation meanings of the morpheme "是".