Introduction 

Most countries seem to have indulged in accelerating their economy under the fierce global competition. What we never imagine is that it is the nature that finally pays the price sometimes worsen than the prediction. To besustainable for future, we human beings should not sacrifice the environment for private profit.

Ø 这里的开头需要注意背景的描述不需要多，一两句就可以切入主题。

 Body 

The first thing should be emphasized is the irreversibility of ecosystem. With such a large diversity of animals and plants, the system is fragile andvulnerable, which means any effect imposed to it will be toodetrimental to bear. Now, let’s turn to what human beings have done. We pour the sewage to the river where fishes and aquatic plants lived; we emit the waste gas to the air which we need to breath in everyday; we invade the remote area that used to be wild animals’ habitats.【抽象话题下可以采用复合例子进行说明】All of these only orient to human being’s profit without any consideration for the potential risks. Well, to be more precise, it has turned into the actual life threats for every aspect of the living environment. The whole world has been trapped by deteriorated surrounding; not only are animals suffering from the continuous extinction, but also human beings are struggling with the environment-related diseases. Isn’t it horrible? We, finally, become the one to swallow the bitter pill.

Ø 先陈述自然的脆弱性及不可逆性

Also, prospering the economy never has an end. Some opponents take inferior situation of the country as an excuse for restlessexploiting where we live. However, how to define the success of being developed? For example, China used to be a country with extremely lowproductivity. In order not to be lagged behind, we spared no effort to dig our land for available resource and thus the last generation has already been surrounded by poor environment. Today, after narrowing the gapwith other developed countries, our government is planning the further goal.【给一个时间跨度的例子说明发展的无限性】There is no denying that the heavily damaged would still be depended on for generating more for the sake of human’s endless desire.

Ø 从经济发展的角度切入陈述不必要性

In a nutshell, I am not declaring that the environment and economic development cannot coexist but the degree should be carefully concerned.

Ø 结尾段一笔带过强化观点