如現代漢語「X像Y一樣（那樣、似的）」、近代漢語「X像Y一般（相似）」以及上古漢語「X如Y然」的這種句式可以稱為「比擬式」。印度人善作譬喻，因此佛經中用作比擬的句子就十分常見，反映在漢譯佛典中比擬式也就特別豐富。東漢魏晉南北朝是佛經傳入的早期階段，也相當漢語史上的中古漢語時期，利用此時的佛典我們可以考察當時比擬式發展的一個過程。中古漢語時期佛典中的比擬式逐漸發展出與上古漢語有異而接近代漢語的形式，此時產生「X如Y一種（等）」「X如Y相似（類）」「X如Y無異」等新句式出來。我們推測，中古漢語的比擬式主要是來自複句的緊縮，並且是仿傚表等同或類同的「與」字式而產生的。至於新句式之所以會取代上古漢語的舊形式，則是因為詞彙複音節化的趨勢。上古漢語的「然」因為沒有適當的雙音節代詞可以取代，於是自表等同或類同的「與」字式移借了「無異」「相似（類）」「一種（等）」等而構成新式。

In this paper, we show that the sentence patterns expressing simile such as “X xiang 像 Y yiyang 一樣 (nayang 那樣, side 似的) ” in Modern Chinese and “X ru 如Y yiban 一般 (xiangsi 相似) ” in Early Mandarin Chinese have their Middle Chinese equivalents, which can be identified as “X ru 如 Y yizhong 一種,” “X ru 如 Y xiangsi 相似,” or “X ru 如 Y wuyi 無異.” Indian people like to speak in similitudes, so sentences expressing simile are very common in Chinese Buddhist sutras. This is why there is a great deal of examples of these forms in Chinese Buddhist sutras. Buddhist sutras were brought to China around the Middle Chinese period. Therefore, by examining the rich Buddhist texts we can observe the process of the development of sentences expressing simile at the time well. In this paper, we propose that the sentence patterns expressing simile in Middle Chinese were mainly derived from the contraction of compound sentences and came into being by the analog of the construction of “X yu 與 Y yizhong 一種 (wuyi 無異, xiangsi 相似)” which expresses likeness or similarity between X and Y. The reason why “wuyi 無異,” “xiangsi 相似,” and “yizhong 一種” could replace the “然” in “X ru 如 Y ran 然” in Old Chinese is because of the tendency for bi-syllablization of lexicons at the time.