给学生一些事情去做，而不是一些东西去学；而这些事情的性质需要思考；学习会自然而然地发生。
Give the pupils something to do, not something to learn; and the doing is of such a nature as to demand thinking; learning naturally results.
我不能没有书。
Fear is the foundation of most governments.
"The world is tough, but you’re tougher."
The fight against viruses is a battle of wits between nature and human ingenuity.