Correct

前事不忘,后事之师

/ qián shì bù wàng hòu shì zhī shī /
Strokes
https://i.cchatty2.com/filters:format(webp)/fit-in/684x0/img/202102/前事不忘后事之师-Chinese-idioms-Cchatty-b731f389-d31e-4d21-9404-e10a2fc49903-1612776525.jpg

Collocation

1
难道不知道什么叫前事不忘,后事之师吗
2
记住前事不忘,后事之师的古训
3
古人说,前事不忘,后事之师

Definition

前事不忘,后事之师

Literally means:

past experience, if not forgotten, may serve as a guide for the future

Actually means:

It means one should draw lessons from the past experiences and take them as a guide in future. It is a written or literary expression.

牢记过去的经验教训,把它作为今后做事的借鉴。书面语。

Example

Used as a minor sentence, or as attributive or object. (作小句、定语、宾语)
1
Qiánshìwàng
前事不忘
  
,
hòushìzhīshī
后事之师
  
wèishénme
为什么
hái
zhème
这么
hu
马虎
ne
  
?
Nándào
难道
wàng
le
shàng
上次
shì
事故
shì
zěnme
怎么
shēng
发生
de
ma
  
?

Don't forget the past, the teacher of the past. Why are you so sloppy? Have you forgotten how the last accident happened?

2
Zhè
shì
xuè
de
jiàoxun
教训
  
,
men
我们
dìng
一定
yào
zhu
记住
qiánshìwàng
前事不忘
  
,
hòushìzhīshī
后事之师
zhè
xùn
古训
  
,
ràng
bēi
悲剧
chóngyǎn
重演
  

This is the lesson of blood, we must remember the past do not forget, the teacher of the past this ancient teaching, do not let the tragedy repeat.

3
zhī
zhīdào
知道
mángàn
蛮干
  
,
zhīdào
知道
shénme
什么
jiào
qiánshìwàng
前事不忘
  
,
hòushìzhīshī
后事之师
  
?

He only knows how to do, how do you know what is called the past do not forget, the teacher of the after-things?