It's very important that we all recycle. In nature, everything can be1again. For example, when an animal dies, it becomes 2animal's food. Nothing is wasted. But humans have created things like plastic bags 3can't be broken down by nature. Our rubbish kills animals and 4water and soil. 5we continue making too much rubbish, the problem will only get worse. If nature can't reuse the rubbish, we must recycle6.

    We should clean up the rubbish we've made because nature can't.

    Recycling is also the right thing to do for another reason. The earth is rich in natural materials like water and trees,7these materials are not endless. We use up our natural materials much8than the earth is able to reproduce them. For example, each year we cut9more that 6,000 square miles of forest. But it takes about 25 years 10a new tree to grow.

    Recycling can help us save the earth, so let's take action right now.

意大利的新工业以高新技术聚集的工业小区为独特的发展模式。

原子能

科学家研究发现，原子（atom）由居于中心的原子核和核外电子构成．构成原子各种微粒的电性和质量见下表．原子核体积很小（半径约为10^﹣14m），如果把原子比做一个庞大的运动场，而原子核只相当于一只蚂蚁．

原子核中蕴藏着巨大的能量，原子核的变化（从一种原子核变化成为另一种原子核）往往伴随着能力的释放．目前人们开发核能的方法有两种：一种是重元素的裂变，如铀的裂变；另一种是轻元素的聚变，如氘、氚、锂等．1克铀全部裂变，释放的能量超过2000千克煤完全燃烧时释放的能量．1克氘经过核聚变可能提供相当于10000升汽油完全燃烧后释放出的能量．根据统计，10吨氦﹣3就能提供中国一年所需的能源总量．

请根据上述材料，回答下列问题：