Don't cast your pearls before swine.莫把珍珠投给猪。
珍珠一般被认为是美丽而珍贵的东西,swine一般都用在贬义,意思是对愚蠢的人来说,给他珍贵的东西也不会懂得其价值,只是白白浪费而已。这条谚语出自《圣经·马太福音》第七章,原文是:“Give not that which is holy unto the dogs, neither cast your pearls before swine, lest they trample them under their feet, and turn again and rend you.”
表示“浪费心机、气力”之意的谚语还有:
Light not a candle to the sun.
白日点烛白费蜡。
A blind man will not thank you for a looking glass.
镜子送给瞎子也不能尽其用。
中国有两句成语“对牛弹琴”与“明珠暗投”,也是类似意思。前者指找错了对象;后者指投错了地方。此外还有:“鲜花插在牛粪上”。
相近意思的谚语可参阅What is the good of a sundial in the shade?