中 and 其中 meaning “among”
中 and 其中 have the same translation, but they are used differently.
The postposition 中
The postposition 中 
can be used to distinguish a part from the whole.
It is placed after a word or a phrase identifying the whole.
can be used to distinguish a part from the whole.
It is placed after a word or a phrase identifying the whole.Examples
警察怀疑他们三人中有一个是犯罪
The police suspect that one of the three men is a criminal
jǐngchá huáiyí tāmen sān rén zhōng yǒu yí ge shì fànzuì
这些人中有一个可能就是他
One of these people could be him
zhèxiē rén zhōng yǒu yí ge kěnéng jiù shì tā
中 is often used in the 在…中 structure. In this case, the meaning is not changed.
A word or a phrase that defines the whole replaces the ellipsis.
structure. In this case, the meaning is not changed.
A word or a phrase that defines the whole replaces the ellipsis.Examples
在我的这些朋友中，还是你最了解我
Of all my friends, you know me best
zài wǒ de zhèxiē péngyou zhōng, háishi nǐ zuì liǎojiě wǒ
老师说要在我们留学生中选出两个人去参加汉语比赛
The teacher said that two of our international students will be selected to participate in a Chinese contest
lǎoshī shuō yào zài wǒmen liúxuéshēng zhòng xuǎnchū liǎng ge rén qù cānjiā hànyǔ bǐsài
The preposition 其中
The preposition 其中 is also used to distinguish a part from the whole.
It is used in complex sentences. It is placed at the beginning of the second part of a sentence.
is also used to distinguish a part from the whole.
It is used in complex sentences. It is placed at the beginning of the second part of a sentence. Pay attention
The first part of a sentence states the whole, the second part of a sentence states the part of the whole.
Scheme
subject
whole
predicate
其中
subject
part of a whole
predicate
Examples
三个人出庭，其中两人被还押候审
Three men were taken to trial, two of whom were improsoned
sān ge rén chūtíng, qízhōng liǎng rén bèi huányā hòushěn
今天妈妈做了好几个菜，其中不少是我爱吃的
My mother prepared a lot of dishes today, many of which I love
jīntiān māma zuò le hǎojǐgè cài, qízhōng bù shǎo shì wǒ ài chī de
我今天买了三件衣服，其中有一件是给你的
I have bought three pieces of clothes today. One of them is for you
wǒ jīntiān mǎi le sān jiàn yīfu, qízhōng yǒu yí jiàn shì gěi nǐ de
其中 is also used with the particle 的 . In this case, it has the meaning "...of them".
For example: "two of them", "some of them".
. In this case, it has the meaning "...of them".
For example: "two of them", "some of them".Scheme
其中的
numeral
classifier
noun
Examples
我们将指出其中的一些主要区别
Let’s point out some of their differences
wǒmen jiàng zhǐchū qízhōng de yìxiē zhǔyào qūbié
看这个句子，这是其中的一个错误
Look at this sentence! One of the mistakes is there
kàn zhè ge jùzi, zhè shì qízhōng de yí ge cuòwù
我有姥姥跟奶奶，但是我只认识其中的一个
I have a grandmother on both my mother’s side and my father’s side, but I know only one of them
wǒ yǒu lǎolao gēn nǎinai, dànshì wǒ zhǐ rènshi qízhōng de yí ge