put on weight 发福了，体重增加
put on 除了表示穿上，还有增加的意思。
She has put on weight.
她发福了。
We also tend to put on weight as we get older.
此外，随着我们年龄的增长，体重也会增加。
You have put on weight.
你发福了。
I'm forever on a diet, since I put on weight easily.
我一直在节食，因为我的体重很容易增加。
pack on the pounds 指的是“迅速地增加体重”。
However, she notes, it certainly doesn't pay to pack on the pounds for a youthful face, because being thin has benefits, too.
然而，她指出，为了面容年轻而拼命增肥也不是明智之举，因为瘦也有瘦的好处。
