出自先秦《荀子·哀公》。鸟被逼得走投无路之时就会用嘴啄人，兽到困窘之时就会用爪抓人，人到穷困潦倒之时就会设计骗人。以鸟兽困窘之时的行为为喻，说明人到穷困潦倒之时便会放弃道德操守的原因。

There’s man all over for you, blaming on his boots that faults of his feet.

I don't have any particular recipe [for developing new proofs] ... It is the reason why doing research is challenging as well as attractive. It's like being lost in a jungle and trying to use all the knowledge that you can gather to come up with some new tricks, and with some luck you might find a way out.

释义：正直仁信，原则处世，宏大包容，依此处世，不用学习世俗的那一套也不会不利。此句强调自然的品质，反对虚伪骄饰。

拉丁美洲是乌托邦与怀旧的大陆。

统治阶级掌握着物质生产的手段；无产阶级仅有的是他们的劳动力。

我不是圣人，我是罪人。