1 PREFIX (置于形容词、副词、名词之前表示反义) Un- is added to the beginning of adjectives, adverbs, and nouns, in order to form words that have the opposite meaning. (置于形容词、副词、名词之前表示反义)
2 PREFIX (置于动词之前表示相反的过程) Un- is added to the beginning of a verb that describes a process, in order to form another verb that describes the reverse of that process. (置于动词之前表示相反的过程)
3 PREFIX (置于动词的过去分词之前构成形容词,表示动作尚未发生) Un- is added to the beginning of the past participle of a verb, in order to form an adjective that means that the process described by the verb has not happened. (置于动词的过去分词之前构成形容词,表示动作尚未发生)