题目

More than two thirds of the world's polar bears will be wiped out ( 消灭) by 2050, according to a shocking new study. By then, scientists say, global warming will have melted 42 percent of the Arctic sea ice. By 2100, only a very few of these important creatures will be left. The report has been produced by the US Geological (地质学的) Survey. The scientists have publicized their findings in the hope of influencing US Interior Secretary (内政部长), Dirk Kempthorne, who has been asked to put polar bears on the US endangered species list. Polar bears depend on floating sea ice as a pla11．在平面直角坐标系中，将抛物线y=x2先向右平移4个单位，再向上平移3个单位，得到抛物线L，则抛物线L的解析式为y=（x-4）2+3．