The Earth Is Our Only Home
   Some people imagine to leave this fearful world, only to come down to earth. Scientists tell us that of all the stars known in the vast universe, the earth is the only planet on which human beings can survive. But now we are facing the risky problems concerning our existence on earth.
   Worldwide environmental deterioration (恶化) is alarming. The earth is plagued with population explosion, energy crisis, lack of food, housing problem and environmental pollution. During the process of industrialization, human beings are pursuing crazily the benefits from the economic growth. Now we have suffered from the results. The overuse of natural resources has affected ecosystem(生态系统) on earth.
   So far some effective results have been achieved. However, this is not enough. To protect our homeland we should show greater concern and pay more attention. Since protecting the earth means guaranteeing the steady development of human societym why should not we preserve the environment as far as possible?
核心剖析  用反问、以提出问题供读者考虑的结尾方式，间接阐述了作者的观点。在经过前面的铺垫、说明之后，这个结尾方法可行可取，毫无强加于人之感。虽然形式是问句，但是意义却是强语势的肯定，具有明显的强调作用。以反问结束全文，往往发人深省、令人回味、引起读者思考。