adult是名詞，沒有比較級和最進階
例句
1、
Why can't you two act like civilized adults?
你們倆爲什麼就不能像有教養的成年人那樣行事呢
2、
Children are admitted only if accompanied by an adult.
兒童必須有成年人陪同方可入場。
3、
Through play， children act out in miniature the dramas of adult life.
透過遊戲，孩子們演出了成年人生活的縮影。
