Necessity and oportunity may make a coward valient. 需要和机会可能使懦夫变成勇士。

　　Necessity (or Need) has (or knows) no law. 需要面前无法律。

　　Necessity is the mother of invention 穷则变，变则通。

　　Necessity knows no law. 铤而走险。

　　Need makes the old wife trot. 人急造反，狗急跳墙。(事急老妪跑。)

　　Needs must when the devil drives. 情势所迫，只好如此。

　　Neglect of health is doctor's wealth. 忽视健康，医生财旺。

　　Never be weary of well doing. 行善莫厌烦。

　　Never cackle till your egg is laid. 事竟成，才声张。

　　Never cast dirt into that fountain of which thou hast sometime durnk. 不要过河拆桥。

　　Never do things by halves. 做事情不要半途而废。

　　Never embark on what comes after without having mastered what goes before. 如未掌握好已学过的东西，切莫从事更深的学习。

　　Never fry a fish till it's caught. 捉到鱼，才煎鱼。

　　Never judge by appearances. 人不可貌相。

　　Never neglect an opportunity for improvement. 抓住大好时机，切莫等闲错过。