2. 外语
  3. With the world’s population estimated to grow from six to nine billion by 2050, researchers, businesses and governments are alre

With the world’s population estimated to grow from six to nine billion by 2050, researchers, businesses and governments are alre

admin2012-02-18  97
问题     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 have on everything from food and water to infrastructure (基础设施) and jobs. Underlying all this【S1】______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【S2】______. sustainable way is the cornerstone (基石) of our nation’s energy security, and will be one of the major【S3】______of the 21st century. Alternative forms of energy — bio-fuels, wind and solar, to name a few — are【S4】______being funded and developed, and will play a growing【S5】______in the world’s energy supply. But experts say that, even when【S6】______, alternative energy sources will likely meet only about 30% of the world’s energy needs by 2050.
    For example, even with【S7】______investments, such as the $93 million for wind energy development【S8】______in the American Recovery and Reinvestment Act, important alternative energy sources such as wind and bio-fuels【S9】______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 【S10】______— both traditional and alternative.
[A] stable               [F] marvelous                   [K] comprise
[B] solutions            [G] included                    [L] competitions
[C] significant          [H] growth                      [M] combined
[D] role                 [I] exactly                     [N] challenges
[E] progress             [J] consist                     [O] certainly
【S4】
选项
答案O
解析 分析空所在的句子结构可知，本句不缺主干成分，故本空应填一副词，[I]和[O]入选。[I]exactly “精确地；确切地”无法使此处语义通顺，故答案为[O]certainly“当然；必定”，表示“替代能源肯定是正在投资和研发的”。
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大学英语四级

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