It-hi (乙烯; Ethene) sī iû nn̄g ê thoàⁿ goân-chú kap kheng goân-chú chó͘-sêng ê iú-ki hòa-ha̍p-bu̍t. Kî-tiong, it-hi ê nn̄g ê thoàⁿ goân-chú sī iōng siang-kiān lâi liân-chiap; i sī siōng-kán-tan ê hi-kēng.