Section A
Directions: In this section, there is a passage with ten blanks. You are required to select one word for each blank from a list of choices given in a word bank following the passage. Read the passage through carefully before making your choices. Each choice in the bank is identified by letter. Please mark the corresponding letter for each item on Answer Sheet 2 with a single line through the centre. You may not use any of the words in the bank more than once.

　　Questions 47 to 56 are based on the following passage.
　　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

47 H growth

48 A stable

49 N challenges

50 O certainly

51 D role

52 M combined

53 C significant

54 G included

55 K comprise

56 B solutions

十五选十的解法分为四步：

一．标注词性，预先分组　

二．浏览全文，预测答案　

三．同性比较，选择唯一　

第三步是关键的一步。对相同词性词汇与原文意思进行比照，选择唯一的答案。利用上下文线索，词的褒贬色彩，平行结构，单复数，时态等解题。

四．带入选项，通读检查　

如何判断所填空格的词性是解题的另外一个关键。具体是：

如果是名词：

语法上作主语或宾语，形式上前有冠词或形容词。

如果是动词：

语法上做谓语，形式上前有情态动词；前有代词、名词、名词性短语，后有副词或介词短语；被动语态；做分词；非谓语（不定式或by后面）等五种情况。

如果是形容词：

语法上做表语或宾语补足语，形式上后有名词；前有副词两种情况。

如果是副词：

语法上就是修饰成分，形式上后有形容词；动词和介词之间；助动词或者情态动词和主动词之间三种情况。 　　

本次十五选十的难度是近几次考试最大的，单词比较生僻，句型结构比较复杂。具体而言，因为选项中只有两个副词，exactly和certainly，三个形容词，stable、signifcant　和marvelous.所以从副词和形容词突破。例如，48题空格后是sustainable，所以空格选择形容词。50题后是动词，说明空格选择副词。我们来看第47题。47题是第一题，其解题可以从前面一句的宾语increase寻到线索，所以答案是growth。