Let's learn about "좀 앉으면 어떠냐?"

비워 둔 의자일 바엔 좀 앉으면 어떠냐 ? : Why don't you sit on the empty chair?

비다 : be empty
비우다 : make something empty like room
두다 : put
비워둔 : become empty by someone <— 비우다 + 어(a suffix makes a verb passive form) + 두다 + ㄴ(a suffix makes a verb completed state)
두다 : put
의자 : chair
비워둔 의자 : the empty chair
~일 바엔, ~라면 : if
좀 : how; please; just
앉다 : sit down
~으면 어떠냐 ?, ~어면 어떠냐 ? : how about ? why don’t you ~~ ?