2017年大学英语四级考试阅读材料（2）

2017年大学英语四级考试阅读材料（2）

　　2011年12月

　　With the world’s population estimated to grow from six to nine billion by 2050, researchers, businesses and governments are already dealing with the impact this increase will have on everything from food and water to infrastructure and jobs. Underlying all this 47 challenges will be the demand for energy, which is expected to double over the next 40 years.

　　Finding the resources to meet this demand in a 48 stable, sustainable way is the cornerstone of our nation’s energy security, and will be one of the major 49 progress of the 21st century. Alternative forms of energy--bio-fuels, wind and solar, to name a few, are 50 certainly being funded and developed, and will play a growing 51 role in the world’s energy supply. But experts say that, even when 52 combined, alternative energy sources will likely meet only about 30% of the world’s energy needs by 2050. For example, even with 53 significant investments, such as the $93 million for wind energy development 54 included in the American Recovery and Reinvestment Act, important alternative energy sources such as wind and bio-fuels 55 comprise only about 1% of the market today.

　　Energy and sustainability experts say the answer to our future energy needs will likely come from a lot of 56 solutions , both traditional and alternative.

　　A stable B solutions C significant D role E progress

　　F marvelous G included H growth I exactly J consist

　　K comprise L competitions M combined N challenges O certainly