un- /ʌn/

• 1. 

  PREFIX Un- is added to the beginning of adjectives, adverbs, and nouns, in order to form words that have the opposite meaning. (用于形容词，副词和名词前)表示“非，否”

  例：

  My father was an unemployed labourer.

  我父亲是一个没工作的劳工。

• 2. 

  PREFIX 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. (用于动词前)表示“做相反的动作”

  例：

  He undressed and draped his clothes neatly over the back of the chair.

  他脱下衣服，然后小心地搭在椅背上。

• 3. 

  PREFIX 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. (用于动词过去分词前)表示“该动词描述的动作并未发生”

  例：

  The theory remains untested.

  该理论仍未经过验证。