*sntlibu unattested未見語料√ tlibutlibu + sn-instrumental focus工具焦點preterite過去式曾用來圍著某物的what was used to surround somethingroot詞根√ tlibuAF主事焦點LF處所焦點PF受事焦點IF工具焦點PRES現在式mtlibu——*stlibuPRET過去式*tmnlibu—*tnlibu*sntlibuFUT未來式*mptlibuDIST遠———