“中介物”用英语怎么说？

钱是人们交换货物最常用的中介物.Money is the commonest medium by which people can exchange goods.脑力是劳动者揭示规律和发明利用规律的中介物的能力,体力是由劳动者自身的生物能所形成的机械力.The structure of labour force represents the relationship and ratio between mental power and ...