例如：Things happened in the past, known as history, is great treasure for us human beings, through and only through studying the past can we gain valuable experience which serves as a means of guiding our development of the society.

例子中作者用了3處逗號(hào)，而事實(shí)上，從句間關(guān)系并非密不可分。我們可以很輕松的分成三句話，作者寫得安心，讀者讀得舒心，做到真正的言必達(dá)意。

History consists of the things happened in the past and it is a great treasure to human beings. Through and only through studying the past thoroughly can we gain valuable experience from history. The historical experience serves as a means of guidance for the new development in the society.

5、避免陳詞濫調(diào)等廢話

例如：For getting a satisfying score, students have to prepare for and review their texts frequently, remember all the knowledge they have learned deep in mind, enlarge their learning if it is possible and so on, especially when examinations are coming. All these efforts, no matter what their aims are, will surely lead to a corresponding paying back.

段中的這一句no matter what their aims are，在整個(gè)上下文表達(dá)上面沒有任何實(shí)質(zhì)性的意義，完完全全是句廢話。