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 an jobs. Underlying all this 47________ will be the demand for energy, which is expect青海著名的癫痫医院ed to double over the next 40 years.
Finding the resources to meet this demand in a 48________, sustainable way is the cornerstone 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__南通青少年羊羔疯治疗______ 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 su小儿癫痫病比较好治疗方法ch 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.
A stable B solutions C significant D role E progress
F marvelous G included H growth I exactly J consist
K com针灸治疗小儿癫痫prise L competitions M combined N challenges O certainly
47. N) challenges
48. A) stable
49. E) progress
50. O) certainly
51. D) role
52. M) combined
53. C) significant
54. G) included
55. K) comprise
56. B) solutions