Correct

千不该,万不该

/ qiān bùgāi, wàn bùgāi /
Strokes

Example

Definition

should never have done sth; deeply regret

1
Qiān
gāi
  
,
wàn
gāi
  
,
gāi
ràng
háizi
孩子
rén
li
夜里
chū
出去
  

I should never have let the child go out alone at night.