: carry coals to Newcastle, bring owls to Athens hold a candle to the sun
n.: A-(me)another !, knock at an open door, bring owls to Athens, carry owls to Athens, send owls to Athens, thrash over old straw, make an unnecessary move, superfluous action, greese the fat pig, a superfluous or unnecessary action, remark, etc.
法文解释
faire un travail superflu, porter de l'eau à la rivière