The preposition 由
How we use it
We use the preposition 由 
to emphasize who is responsible for performing the action or who is the initiator of an action.
We should state 由 before the word that indicates the doer.
to emphasize who is responsible for performing the action or who is the initiator of an action.
We should state 由 before the word that indicates the doer.Scheme
object
由
doer
action
Pay attention
Sometimes such sentences are translated using the passive voice.
Examples
这个项目由你来负责吧
You'll be in charge of this project
zhè ge xiàngmù yóu nǐ lái fùzé ba
这件事是由她引起的
She caused this incident
zhè jiàn shì shì yóu tā yǐnqǐ de
你去过天津，所以这次就由你做导游
You have been to Tianjin, so you will be the guide this time
nǐ qùguò tiānjīn, suǒyǐ zhè cì jiù yóu nǐ zuò dǎoyóu
Pay attention
In this meaning we usually use the preposition 由 in formal speech.
The preposition 由 is often used with the structure 是…的 .
.Scheme
object
是由
doer
action
的
Examples
这个故障是由脚本程序出错造成的
The bug was caused by an error in the script
zhè ge gùzhàng shì yóu jiǎoběn chéngxù chūcuò zàochéng de
他是由姨妈带大的
He was brought up by his aunt
tā shì yóu yímā dàidà de
Differences between 由 and 被
The preposition 由 is similar to the preposition 被 have the same meaning, sometimes they even can be used interchangeably, however there are some slight differences in the usage and contexts.
have the same meaning, sometimes they even can be used interchangeably, however there are some slight differences in the usage and contexts.1) In sentences with the preposition 被, we emphasize the fact that an action has taken place, while in sentences with the preposition 由 we emphasize the doer of an action.
Examples
杯子被他打破了
The mug is broken by him
bēizi bèi tā dǎpò le
杯子由他打破
It was he who broke the mug
bēizi yóu tā dǎpò
Pay attention
In sentences with the preposition 被 we often use the suffix 了 after the predicate, however sentences with 由 we should not use it.
after the predicate, however sentences with 由 we should not use it.
2) In sentences with the preposition 被 we can omit the subject of the action (doer), however in sentences with 由 we cannot.
Examples
自行车被借走了
The bicycle was borrowed
zìxíngchē bèi jièzǒu le
自行车由弟弟借走
The bike was borrowed by my younger brother
zìxíngchē yóu dìdi jièzǒu
3) We can use the preposition 由 in imperative sentence and cannot use the preposition 被 in this case.
Examples
这个项目由你来负责吧
You'll be in charge of this project
zhè ge xiàngmù yóu nǐ lái fùzé ba
4) We usually use the preposition 被 when talking about something negative, while 由 is not.
Examples
这个国家由民选代表统治
The country is governed by elected representatives of the people
zhè ge guójiā yóu mínxuǎn dàibiǎo tǒngzhì