go in one ear and out the other 左耳进右耳出;一耳进一耳出;左耳朵进右耳朵出

【例句】
It's no use talking to him, for your word will go in one ear and out the other.
跟他讲没有用，他总是一耳进一耳出。

The teacher keeps telling the pupils to work harder but her words go in one ear and out the other.
老师一再告诫学生们更努力地学习，可她的话被当成了耳旁风。