shāng / jiā / bù / néng / wèi / le / jiàng / dī / chéng / běn / jiù / wǎng / niú / nǎi / lǐ / chān / shuǐ

商家不能为了降低成本就往牛奶里掺水。

Businesses must not dilute milk with water just to reduce costs.