Correct

卖力气

/ màilìqi / 
Strokes

Definition

to make a living doing manual labor/to give sth all one's got

Example

As a Verb

do one's very best; exert all one's strength; exert oneself to the utmost

1
Tā
他
xuéxí
学习
fǎyǔ
法语
hěn
很
mài
卖
lìqi
力气
  
。

He works hard at his French study.

2
Tā
她
kěnéng
可能
yǒudiǎn
有点
màn
慢
  
,
dàn
但
què
却
shì
是
gè
个
kěn
肯
mài
卖
lìqi
力气
de
的
rén
人
  
。

She may be slow, but she always does her best.

As a Verb

live by the sweat of one's brow; make a living by manual labour

3
Mài
卖
lìqi
力气
yǎngjiāhúkǒu
养家糊口

support one's family by manual labour