Never try to teach one's grandma to suck eggs grandma, try, Never, eggs, suck

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Never try to teach one's grandma to suck eggs.不要班门弄斧。
　　Egg是"蛋"的意思，还可以引申为"人、家伙"或者是蛋状物。
　　Bad egg是坏蛋的意思，而Old egg指人，即"老家伙"的意思。考试吃鸭蛋，英文可以说：to get a goose egg/duck egg。喝酒喝高了，是full as an egg。而lay an egg，字面意思是下蛋，而这句话：He laid an egg telling a joke.意思却是讲笑话讲砸了。所以，任何事情laid an egg就是说失败了、搞砸了。所以，做任何事情都应该walk / tread on / upon eggs小心翼翼地行事。Egg的习惯用法很多：
　　from the egg to the apple自始至终
　　He that would have eggs must endure the cackling of hens. 想要吃鸡蛋，就不得不听母鸡叫。(要享受就得先吃苦)
You can't make an omelet without breaking eggs. 不可能不付出代价而有所得。(omelet是一种蛋饼)
　　Never cackle till your egg is laid. 蛋没下来之前别咯咯叫。(事未成功，切莫张扬)
　　Don't put all your eggs in one basket. 不要把全部希望寄托於一次机会上。
　　此外，不要班门弄斧还可以说：
Never offer to teach fish to swim.