要做好选词填空题，必须要在熟悉选项、通读全文、把握文章结构与大意的前提下，根据所提供的词汇及句子的结构、语法和语篇等信息，通过逻辑推理、对比等手段最后确定答案。环球博海四六级小编特整理了2014年6月英语四级阅读之选词填空习题(31)，以供2014年广大备考的考生参考!

　　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 (基础设施) and jobs. Underling all this 47 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 . sustainable way is the cornerstone (基石) of our nation's energy security, and will be one of the major 49 of the 21st century. Alternative forms of energy- bio-fuels, wind and solar, to name a few are 50 being funded and developed, and will play a growing 51 in the world's energy supply. But experts say that even when 52 , alternative energy sources will likely meet only about 30% of the world's energy needs by 2050.

　　For example, even with 53 investments, such as the $93 million for wind energy development 54 in the American Recovery and Reinvestment Act, important alternative energy sources such as wind and bio-fuels 55 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 both traditional and alternative.

　　注意：此部分试题请在答题卡2上作答。

　　A)stable I)exactly

　　B)solutions J)consist

　　C)significant K)comprise

　　D)role L)competitions

　　E)progress M)combined

　　F)marvelous N)challenges

　　G)included O)certainly

　　H)growth