Nature is the true law.

　　天行有常，不為堯存，不為桀亡。

　　Necessity is the mother of invention.

　　需要是發明的動力。

　　Never fish in trouble water.

　　不要混水摸魚。

　　Never judge from appearances.

　　不可以貌取人。

　　Never say die.

　　永不言敗。

　　Never too old to learn, never too late to turn.

　　亡羊補牢，為時未晚。

　　New wine in old bottles.

　　舊瓶裝新酒。

　　No cross, no crown.

　　不經歷風雨，怎么見彩虹。

　　No garden without its weeds.

　　沒有不長草的園子。

　　No living man all things can.

　　世上沒有萬事通。

　　No man can do two things at once.

　　一心不可二用。

　　No man is born wise or learned.

　　沒有生而知之者。

　　No man is content.

　　人心不足蛇吞象。

　　No man is wise at all times.

　　聰明一世，糊涂一時。

　　None are so blind as those who won't see.

　　視而不見。

　　None are so deaf as those who won't hear.

　　充耳不聞。

　　No news is good news.

　　沒有消息就是好消息。

　　No one can call back yesterday.

　　昨日不會重現。

　　No pains, no gains.

　　沒有付出就沒有收獲。

　　No pleasure without pain.

　　沒有苦就沒有樂。

　　No rose without a thorn.

　　沒有不帶刺的玫瑰。

　　No sweet without sweat.

　　先苦后甜。

　　No smoke without fire.

　　無風不起浪。

　　Nothing brave, nothing have.

　　不入虎穴，焉得虎子。

　　Nothing dries sooner than a tear.

　　眼淚干得最快。

　　Nothing in the world is difficult for one who sets his mind to it.

　　世上無難事，只怕有心人。

　　Nothing is difficult to the man who will try.

　　世上無難事，只要肯登攀。

　　Nothing seek, nothing find.

　　沒有追求就沒有收獲。

　　Nothing is so necessary for travelers as languages.

　　外出旅行，語言最要緊。

　　Nothing is to be got without pains but poverty.

　　世上唯有貧窮可以不勞而獲。

　　Not to advance is to go back.

　　不進則退。

　　Not to know what happened before one was born is always to be a child.

　　不懂世故，幼稚可笑。

　　No way is impossible to courage.

　　勇者無懼。

　　Obedience is the first duty of a soldier.

　　軍人以服從命令為天職。

　　Observation is the best teacher.

　　觀察是最好的老師。

　　Offense is the best defense.

　　進攻是最好的防御。

　　Old friends and old wines are best.

　　陳酒味醇，老友情深。

　　Old sin makes new shame.

　　一失足成千古恨。

　　Once a man and twice a child.

　　一次老，兩次小。

　　Once a thief, always a thief.

　　偷盜一次，做賊一世。

　　Once bitten, twice shy.

　　一朝被蛇咬，十年怕井繩。

　　One boy is a boy, two boys half a boy, three boys no boy.

　　一個和尚挑水喝，兩個和尚抬水喝，三個和尚沒水喝。

　　One cannot put back the clock.

　　時鐘不能倒轉。

　　One eyewitness is better than ten hearsays.

　　百聞不如一見。

　　One false move may lose the game.

　　一著不慎，滿盤皆輸。

　　One good turn deserves another.

　　行善積德。

　　One hour today is worth two tomorrow.

　　爭分奪秒效率高。

　　One man's fault is other man's lesson.

　　前車之鑒。

　　One never loses anything by politeness.

　　講禮貌不吃虧。

　　One swallow does not make a summer.

　　一燕不成夏。

　　One's words reflect one's thinking.

　　言為心聲。

　　Out of debt, out of danger.

　　無債一身輕。

　　Out of office, out of danger.

　　無官一身輕。

　　Out of sight, out of mind.

　　眼不見，心為靜。