题目内容：
Are you facing a situation that looks impossible to fix? In 1969, the pollution was terrible along the Cuyahoga River near Cleveland, Ohio. It 56(be) unimaginable that it could ever be cleaned up. The river was so polluted that it57(actual) caught fire and burned. Now, years later, this fiver is one of58most outstanding examples of environmental cleanup.
But the fiver wasn' t changed in a few days59even a few months. It took years of work to reduce the60(industry) pollution and clean the water. Finally, that hard work paid off and now the water in the fiver is61(clean) than ever.
Maybe you are facing an impossible situation. Maybe you have a habit62is driving your family crazy. Possibly you drink too much or don' t know how to control your credit card use. When you face such an impossible situation, don't you want a quick fix and something to change immediately?
While there are63(amaze) stories of instant transformation, for most of us the64(change) are gradual and require a lot of effort and work, like cleaning up a polluted river. Just be65(patience).
阅读以上短文,回答题.
第56题应填__________
参考答案：
答案解析：