English主要词典
un-
Universal Words
prefix
1 (in adjectives, adverbs and nouns) not; the opposite of:
unable * unconsciously * untruth * un-American concepts such as subsidized medical treatment and free education (= not typical of the US) * un-American activities (= against the interests of the US)
2 (in verbs that describe the opposite of a process):
unlock * undo * unfold