bāng máng
你搬家时我来帮忙
nǐ bān jiā shí wǒ lái bāng máng
I'll come help you when you move.
这件事我实在帮不上忙。
zhè jiàn shì wǒ shízài bāng bù shàng máng.
I really can't help with this matter.