Yesterday is dead, forget it; tomorrow does not exist, don't worry; today is here, use it.    昨天已经消逝，把它忘掉；明天还未来到，不必烦恼；今天就在眼前，把它用好.
Yesterday will not be called again.    光阴一去不复返.
You (or One) cannot make a silk purse out of a sow's ear.    粗瓷碗雕不出细花来.
You are the greatest enemy if you are a coward, but if you are brave, you are your greatest friend.    如果你是胆小鬼，你就是自己最大的敌人；如果你是勇敢者，你就是自己最好的朋友.
You can do more than strike while the iron is hot; you can make the iron hot by striking.    铁热时，你能做的不止是锤打，而锤打可使铁热.
You can fool some of the people all the time, and all of the people some of the time; but you can't fool all of the people all the time.    你可以一直愚弄一些人，甚至可以在某个时期愚弄所有的人；但不能一直愚弄所有的人.
You can take a horse to the water but you cannot make him drink.    马到河边不喝水，逼马低头亦枉然.
You cannot burn the candle at both ends.    蜡烛不能两头点，精力不可过分耗。
You cannot clap with one hand.    孤掌难鸣.
You cannot eat your cake and have it.    鱼与熊掌，不可得兼。
You cannot flay the same ox twice.    一头牛不能剥两次皮.
You cannot have two forenoons in the same day.    一日之中不可能有两个上午.
You cannot have your cake and eat it.    你不能又要留饼，又要吃它。
You cannot judge a tree by its bark.    人不可貌相.
You cannot make a crab walk straight.    江山易改，本性难移.
"You cannot put old heads on young shoulders.
"    "少年老成，势必难解。
"
You cannot sell the cow and sup the milk.    你不可能出售乳牛，同时又要喝牛奶.
You can't eat your cake and have it.    不能既要吃饼，又要把饼保存.
You can't make bricks without straw.    没有稻草，制砖难搞.
You can't make omelets (or omeletts) without breaking eggs.    有失才有得.
You have no goats, and yet you sell kids.    你虽无老山羊，却出卖小山羊. joozone.com