Modern Chinese confirmative shi (as in mei cuo, wo shi yao dusi ni (沒錯，我是要毒死你) ‘that’s right. I really wanted to poison you to death’) is not an auxiliary but an adverb. It derives from the adjective shi ‘true, real’ in Old Chinese (Yan zhi yan shi ye (偃之言是也) ‘what Yan said was true’). The grammaticalization pathway of the Modern Chinese confirmative shi is different from that of the copula shi (Laozhang shi huoche siji (老張是貨車司機) ‘Laozhang is a truck driver’) or the auxiliary shi (Laozhang shi kai huoche, wo shi kai keche (老張是開貨車，我是開客車) ‘Laozhang drives a truck and I drive a coach car’). Modern Chinese confirmative shi, copula shi, and auxiliary shi have the same morphological form because they all appear to derive from the adjective shi or demonstrative ( shi ke ren, shu bu ke ren (是可忍，孰不可忍) ‘if this could be endured, is there anything else that could not be endured’) in Old Chinese. Such a pattern of morphological sameness seems to be cross-linguistically rare, if not unique.

中文翻译：

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现代汉语确证式

现代汉语确认词（如mei cuo, wo shi yao dusi ni (对，我是要毒死你) '是的。我真的很想毒死你'）不是助词，而是副词。它源自古汉语中的形容词“真、真”（偃之言是也）。现代汉语确证式的语法化路径不同于系词式（Laozhang shi huoche siji（老张是货车司机）“老张是货车司机”）或助词（Laozhang shi kai huoche, wo shi kai）的语法化途径。 keche（老张是开货车，我是开客车）“老张开货车，我开客车”）。现代汉语的肯定式 shi、copula shi 和助动词 shi 具有相同的形态形式，因为它们似乎都源自形容词 shi 或指示词（shi ke ren, shu bu ke ren (shi ke ren, shu bu ke ren (shi ke ren, shu bu ke ren (shi ke ren, shu bu ke ren (shi ke ren, shu bu ke ren (shi ke ren, shu bu ke ren (shi ke ren, shu bu ke ren (shi ke ren, shu bu ke ren (shi ke ren, shu bu ke ren (是可忍，孰不可忍))'if this can忍受，在古汉语中还有什么不能忍受的')。这种形态相同的模式似乎在跨语言上是罕见的，如果不是独一无二的话。