阅读下面这首宋诗，完成后面题。

和子由渑池怀旧

苏轼

人生到处知何似？应似飞鸿踏雪泥。泥上偶然留指爪，鸿飞那复计东西？

老僧已死成新塔，坏壁无由见旧题。往日崎岖还记否？路长人困蹇驴嘶③。

【注】①嘉佑六年（1061年），作者赴任陕西路过渑池。其弟苏辙送至郑州，然后返回京城开封。写了《怀渑池寄子瞻兄》寄赠。作者遂作此和诗。②据苏辙所注，兄弟二人昔日一同应举，过渑池县寺舍，曾在老僧奉闲的僧房壁上题诗。③苏轼自注“往岁，马死于二陵，骑驴至渑池”。

    Climate change has had a number of effects on cities around the world, including rising see levels. And, this has become an especially big problem for coastal cities. City officials must now prepare for higher tides on their coasts. The American city of Miami is one example. Located in South Florida, Miami is home to nearly 3 million people and billions of dollars in land and buildings.

    Miami is one of the cities in America most at risk for rising sea levels. The waterfront is central to Miami's culture and economy. But as the seas rise with climate change .the water will not stay put. Large parts of South Florida are in danger of being under water in the coming years. Across Biscayne Bay, the City of Miami Beach is making improvements - raising streets, adding water pumps and more.

    It is costing the city a lot of money. Local communities will spend 500 million dollars for the improvements. Thankfully, the residents, the folks that are paying the bill for this work, realize that the cost of doing nothing is much greater. A possibility officials are discussing with residents is for city to buy homes in some places where flooding has been a problem. The city would then turn that land into parks of grassland that could hold the water.

    Over time, the city may need to take bigger risks. Miami's future depends largely on how much, and how fast, the oceans rise.

    Caroline Lewis leads the climate activism group, the CLEO Institute. She says cities cannot avoid the need to move inland. But, she says，a well-planned withdrawal (撤退) could include measures to keep people safely in place for as long as possible. And, she says, the world could learn from such a model. In these two Florida cities built on wetlands, there remains a lot of hopefulness.