There are two main causes of cancer: heredity and environment. We can do nothing to change our heredity, that is, the basic physical characteristics that were passed on to us by our parents. However, we can do a GREat deal to control our environment, which may account for 80-90 %of all cancers.
Environmental pollution can be divided into two kinds: personal and impersonal. Personal pollution may be defined roughly as unhealthy habits such as smoking, drinking, and eating the wrong foods. Clearly, with enough will power we can control this personal environment.
Impersonal pollution, on the other hand, refers to those things which are beyond our individual control. One example would be industrial pollution, which is very hard to control because of the expense involved. It would be expensive in terms of profits and perhaps jobs. The American automobile industry, for example, resisted the law requiring smog-control devices because it feared the added expense would reduce profits. Nevertheless, some laws protecting the environment have been quite successful in reducing pollution.
原因有两个：癌症的遗传和环境。我们可以做什么来改变我们的遗传，即，被传递到我们的父母的基本物理特性。然而，我们可以做很多事情来控制我们的环境，这可能占80-90%的癌症。
环境污染可分为两种：个人和非个人的。个人的污染可能是定义大致为不健康的生活习惯，如吸烟，饮酒，吃错食物。显然，有足够的意志力，我们可以控制自己的环境。
客观的污染，另一方面，是指那些超出我们的个人控制。一个例子是工业污染，这是很难控制，因为所涉及到的费用。它将在利润方面是昂贵的和可能的工作。例如，美国汽车工业，抵制法律要求烟雾控制装置是担心增加的支出将减少利润。然而，一些法律保护环境减少污染已经相当成功。
