取两份质量相等的有机物M，一份与足量的钠反应放出气体V₁升，另一份与Na₂CO₃溶液反应最多放出气体V₂升；若同温同压下V₁＞V₂＞0，则M可能是（     ）

A．CH₃COOH

B．HOOC—COOH

C．HO(CH₂)₂CHO

D．

—Mum, I want some pocket money.

—Well. I won’t give it to you __________ you wash your clothes.

A．if

B．unless

C．while

D．though