The beauty of mathematics is that it is so simple yet so powerful.
"The line between hero and villain is often thinner than we think."
采矿业必须发展以满足不断变化的世界的需求。
与没见过的老虎还可以亲近,但与很熟悉的人不能够太亲。
工商业和农业一样都是国家的根本