Correct

趁空

/ chèn kōng / 
Strokes

Example

As a Verb

use one's spare time; avail oneself of leisure or an opportunity

1
Zhè
这
shì
事
bù
不
jí
急
  
,
chèn
趁
kōng
空
zài
再
zuò
做
  
。

Do it at your leisure; it's not urgent.

2
Chèn
趁
kōnghé
空合
yī
一
xià
下
yǎn
眼

catch a few winks when there is time