乳糖不耐症患者体内通常缺乏足够的乳糖酶来分解牛奶中的乳糖。

People with lactose intolerance usually don't have enough ___lactase to break down the sugar in milk.

如果你有乳糖不耐症，可以在喝牛奶前服用乳糖酶补充剂。

If you're lactose intolerant, you can take ___lactase supplements before drinking milk.