The Mandarin Chinese particle zài - ? has several functions. It is most commonly used to indicate location. When used before a place word, zài means “on” “at” or “in”.

Location - Zài

Here are some examples of zài as a location word:

Ta zài jia.
He is at home.
???｡

Shu zài nàli.
The book is there.
(trad) ????｡
(simp) ????｡

Tamen zài huoche zhàn.
They are at the train station.
(trad) ??????｡
(simp) ??????｡

The negative forms of location phrases are formed by placing bù - ? before zài - ?.

Note that when bù is placed directly before a fourth-tone syllable like zài, the fourth tone of bù changes to a rising 2nd tone.

Ta bú zài jia.
He is not at home.
????｡

Shu bú zài nàli.
The book is not there.
(trad) ?????｡
(simp) ?????｡

Tamen bú zài huoche zhàn.
They are not at the train station.
(trad) ???????｡
(simp) ???????｡

Questions are formed with either the question particle ma – ? or the positive / negative sentence form - zài bú zài. Question adverbs such as nali - ?? can also be used:

Ta zài jia ma?
Is he at home?
??????

Shu zài nali?
Where is the book?
(trad) ?????
(simp) ?????

Tamen zài bú zài huoche zhàn.
Are they at the train station?
(trad) ?????????
(simp) ?????????

Preposition - Zài

Zài is also used as a preposition to indicate where an action takes place:

Tamen zài chúfáng chi dongxi.
They are in the kitchen eating.
(trad) ????????｡
(simp) ????????｡

Continuing Action - Zài

Another use for zài - ? is to show that an action is occurring at the present moment. Zài is placed before the verb it modifies:

Tamen zài kàn diànshì.
They are watching TV.
(trad) ??????｡
(simp) ??????｡

Ta zài kaoshì.
She is writing an exam.
(trad) ????｡
(simp) ????｡

Yisheng zài zhen huànzhe.
The doctor is examining a patient.
(trad) ?????｡
(simp) ?????｡

See also: zài and location words.