21.词组：trace elements

释义：微量元素

例句：Iron andzinc are two important trace elements that the human body needs.

22.词组：protein-rich

释义：富含蛋白质的

例句：Manydieticians believe that protein-rich diets are best at keeping weight off.

23.词组：have a sweet tooth

释义：喜欢吃甜食

例句：I can’tresist cakes and candy bars because I have a sweet tooth.

24.词组：be a gourmet

释义：一个美食家

例句：Molly isa gourmet, an excellent judge of food and drinks.

25.词组：be mouth-watering

释义：让人垂涎欲滴的

例句：She gaveme a recipe for the mouth-watering chocolate cakes.