Correct

雷打不动

/ léi dá bù dòng /
Strokes

Definition

not shaken by thunder (idiom); the arrangements are unalterable/to adhere rigidly to regulations/will go ahead whatever happens (of an arrangement or plan)

Example

Definition

not to be shaken by thunder―not to be altered under any circumstances; unshakable; unyielding

1
měitiān
每天
jiānchí
坚持
chénliàn
晨练
  
,
léidòng
雷打不动
  

His doing exercises in the morning has never stopped for a single day.

Related

雷打不动