Adverb

Potential content

Can't be reduplicated (although reduplicated adjectives can be converted into adverbs with 地, e.g. 急急匆匆地).
Can't be used as answers to questions.
Can't modify nouns.
Can't precede subjects (in general).
Some adverbs can function as linking words (conjunctions). E.g. 就
Always appear before a verb or adjective.
都
也
又 and 再
- 又 for past repetition. The event has happened twice.
- 再 for repetition in the future. The event has happened once so far.
- 又 may be used for future events if they are definitely going to occur, such as days of the week: 明天又是星期三了.