The teacher must have told him a hundred times, and he always forgets it's like water off a duck's back.

◆like water off a duck's back
字面词义：就像水从鸭子的背上流走一样。
真正含义：毫无影响；不起作用；被当作耳边风。

◆句子翻译
老师同他说过上百次，可他总是记不住——他把老师的话当成了耳边风。

1、He always forgets something which his friends said, maybe it's like water off a duck's back.
他总是忘记一些他朋友对他说过的事情，也许他把这些当成了耳边风了吧。
2、The scolding ran off him like water off a duck's back.
他听了责骂只当耳边风。
3、Their criticisms of his talk rolled off him like water off a duck’s back.
他们对他的谈话所作的批评，他根本不理会。
4、Their hints about his behavior were (like) water off a duck's back.
他们示意他举止不当，如同对牛弹琴。

5、That guy is hopeless. All my admonitions are like water off a duck's back.
那个家伙真是不可救药，我的一切警告他都当作耳边风。
6、To the seasoned campaigner, the remarks of hecklers were like water off a duck's back.
对老练的竞选者来说，质问者的话有如耳边风。
7、Jack doesn't care what people say. Criticism rolls off him like water off a duck's back.
不管别人说什么，杰克都不往心里去。他对于批评是满不在乎的。
8、I kept telling the boys not to bang doors but is was like water off a duck’s back.
我再三告诫孩子们不要把门关得砰砰响，但我的话对他们来说如同耳旁风。