I don't know how you can eat so much yet never put on any weight.

　　重点

　　put on weight意为“体重增加，发福”。该句意为“我不明白，为什么你吃这么多却长不胖呢?”

　　考点归纳

　　与weight有关的口语词汇和短语还有：

　　overweight(超重)，口语中一般不说He is fat，而会委婉地表达为He is overweight，因为fat是不礼貌的用词。

　　gain weight(长胖)，相当于put on weight。与此相对的短语是lose weight(减肥)。如：

　　Gaining weight can be as challenging to some people as losing weight is to others. 对于有些人来说，增加体重的难度几乎相当于另一些人减肥的难度。

　　gross weight意为“毛重”。如：

　　The gross weight of the box of chocolates is 500 grams. 那盒巧克力的总重量(毛重)是500克。