《淮南子·说山训》里说:“以小明大,见一叶落而知岁之将暮,睹瓶中之冰而知天下之寒。”我们无法一眼望尽整片秋野,但我们可以从一片落叶知道秋天的到来。写作文也是一样,在有限的篇幅和时间里我们无法写尽所有,但是我们也可以挑一些有代表性的细节去表现全局。所以写作文很关键的一步就是要找到那片树叶然后对其进行细致的描写, “Huainanzi said the mountain training”, said: “To the small Mingda, see a fall and the age of the twilight, see the bottle of ice and the world know the cold.” "We can not look at the whole piece of autumn fields, But we can know the fall from a fallen leaf. The same applies to writing essays. We can not do everything in limited space and time, but we can also pick up some representative details to show the whole picture. So writing a very crucial step is to find the leaves and then carry out a detailed description of it,