Cast pearls before swine.對牛彈琴。To sing for them is to cast pearls before swine.為他們唱歌真是猶如對牛彈琴。Their hints about his behaviour were (like) water off a duck"s back.他們示意他舉止不當,如同對牛彈琴.He has no ear for music. It"s casting pearls before swine to take him to the concert.他不懂音樂，帶他去聽音樂會，猶如對牛彈琴。Trying to get Paul to agree to spend more money on amenities is like talking to a brick wall.要想說服保羅在使用便利設施上多花些錢如同對牛彈琴。He explained the beauty of the music to her but it was casting pearls before swine.他向她講解那音樂的妙處，可是這無異於對牛彈琴。He explained the beauty of the music to his wife but it was casting pearls before swine.他跟他妻子講解那音樂之美，可是這無異於對牛彈琴。Jokes are lost on him.對他講笑話是對牛彈琴。Never cast your pearls before swine.不要把珍貴之物送給不識貨的人；勿明珠暗投；勿對牛彈琴。