彼此 "each other"
The pronoun 彼此 
can serve as a subject, an object, or an attribute.
When 彼此 serves as the subject, it is placed either before a verb or a verb phrase.
can serve as a subject, an object, or an attribute.
When 彼此 serves as the subject, it is placed either before a verb or a verb phrase.Examples
我们是一个团队，彼此应该多沟通
We are a team and we should communicate more with each other
wǒmen shì yí ge tuánduì, bǐcǐ yīnggāi duō gōutōng
相处久了，彼此可以从表情中了解对方的意思
We have a tacit understanding of each other after spending a long time together
xiāngchǔ jiǔ le, bǐcǐ kěyǐ cóng biǎoqíng zhōng liǎojiě duìfāng de yìsi
When 彼此 serves as an object, it is placed after a two-syllable verb.
Examples
你们要帮助彼此
You guys should help each other
nǐmen yào bāngzhù bǐcǐ
好朋友总是会陪伴彼此
Good friends can always keep each other company
hǎo péngyou zǒngshì huì péibàn bǐcǐ
When 彼此 serves as an attribute, it is placed before a noun. In this case, the particle 的 must be placed between 彼此 and the noun.
must be placed between 彼此 and the noun.Examples
过去一年 ，我们见证了彼此的进步
Over the past year, we have witnessed each other's progress
guòqù yì nián, wǒmen jiànzhèng le bǐcǐ de jìnbù
In spoken language, 彼此 can be reduplicated.
In this case, 彼此彼此 has the meanings "the same to you", "to be alike" and "to be in a similar position".
Examples
你的家真不错！—— 彼此彼此！
What a nice home you have! — Same for you!
nǐ de jiā zhēn búcuò — bǐcǐ bǐcǐ
那么你也没找到工作？咱们彼此彼此！
You haven't found a job yet? Same here!
nàme nǐ yě méi zhǎodào gōngzuò? zánmen bǐcǐ bǐcǐ
Pay attention
不分彼此 is a phrase that need to be memorized.
is a phrase that need to be memorized.Learn more