Correct

奋战

/ fènzhàn /
Strokes

Definition

to fight bravely/(fig.) to struggle/to work hard

Example

As a Verb

fight bravely/courageously; work strenuously

1
Jīngguò
经过
sān
yuè
de
jiān
艰苦
fènzhàn
奋战
  
,
jiāng
大江
zhōng
终于
jiéliú
截流
chénggōng
成功
  

After three months'strenuous labour, we finally succeeded in damming the great river.

2
xuèfènzhàn
浴血奋战

fight a bloody battle

3
日夜
fènzhàn
奋战

work hard day and night