先阅读短文，然后根据短文内容从方框内所给的单词中选择恰当的词（注意词形变化）填入短文空白处，使短文完整、通顺。一词只用一次，一空限填一词。方框中有两个词是多余的。将能填入空白处的答案写在答题卡上的相应题号后。

   The world itself is becoming much smaller by using modern traffic and modern communication. Life today is much ____  than it was hundreds of years ago, but it has brought new problems. One of the biggest is ____ . To pollute means to make things dirty. Pollution comes in many ways. We see it, drink it and even hear it.
   Man has been polluting the earth. The more people are, the more pollution is. Many years ago, the problem was not so  ____  because there were not so many people. When the land was ____   up or the river was dirty in a place, men moved to another one. But this is no ____   true. Man is now slowly pollution the ____  world.
   Air pollution is still the most serious. It’s bad to all living things in the world, but it is not ____ one kind of pollution. Water pollution ____  our fish and pollutes our drinking water. Noise pollution makes us become angry more easily.
   Many countries are making rules to ____  pollution. They stop the people from burning coal in houses and factories in the city, and from blowing dirty smoke into the air. The pollution of SO2 is now the most dangerous problem of air pollution. It is caused by heavy traffic. It is certain that if there are fewer people driving, there will be ____  air pollution.
   The earth is our home. We must take care of it. That means ____  the land, water and air clean.

    Have you read the book called Uncle Tom's Cabin? It's said that it is one of the greatest books in America．The book ____an unpleasant social problem—slavery(奴隶制)in the Southern States of America. It first came out in 1852．Over 300,000____were sold out in a year．People had ____ideas about the book．In the North, more and more people began to____theft support(支持)for the freedom(自由)for the black people after they read the book, but in the South, many people were very____at the people in the North. In 1861, the war between the two parts of the country____. Uncle Tom's Cabin surely played a part in the ____. In 1862, Abraham Lincoln met Harriet Beecher Stowe, the book's ____. As he took her hand. Lincoln said, "So this is the little lady who started this big war."

社会的进步离不开改革，改革是历史发展的强大动力，对社会进步起着巨大的推动作用。它是落后国家通向现代化的“桥梁”。懂得改变，是一种智慧。结合所学知识，回答问题