have a weakness for 特别爱好，偏爱，对...毫无抵抗力

　　I have a weakness for your son.

　　我对你儿子毫无抵抗力。

　　Oh! You have a weakness for sweets, too!

　　哦！原来你也挡不住甜食的魅力！

　　疯狂练习吧！