下面的短文后有2项测试任务：(1)第23-26题要求从所给的6个选项中为第2～5段每段选择1个最佳标题；(2)第27～30题要求从所给的6个选项中为每个句子确定1个最佳选项。
Natural Gas
Natural gas is produced from reservoirs deep beneath the earth's surface．It is a fossil fuel，meaning that it is derived from organic material buried in the earth millions of years ago.The main component of natural gas is methane(甲烷).
The popularity and use of clean natural gas has increased dramatically over the past 50 years as Dipeline infrastructure(基础设施)has been installed to deliver it conveniently and economically to millions of residential，commercial and industrial customers worldwide．Today，natural gas service is available in all 50 states，and is the leading energy choice for fueling American homes and indus-tries．More than 65 million American homes use natural gas．In fact，natural gas is the most eco-nomical source for home energy needs，costing one-third as much as electricity. In addition to heat-ing homes，much of the gas used in the United States is used as a raw material to manufacture a wide variety of products，from paint，to fibers for clothing，to plastics for healthcare，computing and fur-nishings． Natural gas is also used in a significant number of new electricity-generating power plants.
Natural gas is one of the safest and cleanest fuels available． It emits less pollution than other fossil fuels．dioxide(二氧化碳)and water vapor-the same substances emitted when humans ex-hale．Compared with some other fossil fuels，natural gas emits the least amount of carbon dioxide in-to the air when combusted(燃烧)-making natural gas the cleanest burning fossil fuel of all．The industry also is subject to substantial federal regulation in the areas of production and distribution，which help ensure it is provided to consumers safely and cleanly．
The United States consumes about one-third of the world's natural gas output，making it the lar-gest gas consuming region in the world．The U．S．Department of Energy's Energy Information Ad-ministration forecasts that natural gas demand will grow by more than 50 percent by 2025.
There are huge reserves of natural gas beneath the earth's surface．The largest reserves of natu-ral gas can be found in Russia，West and North Africa and the Middle East．LNG(液化天然气)has been produced domestically and imported in the United States for more than four decades.To-day，the leading importers of LNG are Japan，Korea，France and Spain.
23．Paragraph 2_______________
24．Paragraph 3_______________
25．Paragraph 4_______________
26．Paragraph 5_______________
A．Popularity and use of natural gas
B．Natural gas reserves and supply
C．Natural gas prices
D．Clean fuel of choice
E．Disadvantages of natural gas
F．Natural gas consumption
27．Natural gas is stored deep________.
28．Natural gas is recognized as the most economical energy source ________.
29．When manufacturing many products，people commonly use natural gas ________.
30．It is estimated that by 2050 that natural gas demand in the United States will increase________.
A．over the past 50 years
B．beneath the earth surface
C．by more than 50 percent
D．for more than four decades
E．as a raw material
F．for home energy needs
第4部分：阅读理解(第31-45题，每题3分，共45分)
下面有3篇短文，每篇短文后有5道题。请根据短文内容，为每题确定1个最佳选项。
第一篇
Walking to Exercise the Brain
Do you think sitting and studying all the time will improve your grades?Think again．Getting some exercise may help，too．
New research with older people suggests that taking regular walks helps them pay attention better than if they didn't exercise．
Previous research had shown that mice learn，remember，and pay attention better after a few weeks of working out on a running wheel．Mice that exercise have greater blood flow to the brain than those who don't．Their brain cells also make more connections． (www.qidian55.com)编辑整理
Neuroscientists from the University at Urbana-Champaign wanted to find out if the same thing is true for people．First，they measured the physical fitness of 41 adults，ages 58 to 77，after each per-son walked 1 mile．Then，participants looked at arrows on a computer sczeen and had to use com-puter keys to show which way one particular arrow was pointing．
Adults who were physically fit were faster at the arrow task，and their answers were just as ac- curate as their less-fit peers,the researchers found．The fitter participants also had more blood flow to a part of their brain responsible for paying attention and making decisions．
In a second study，15 elderly people who completed a 6-month aerobic-training course were fas-ter at attention tasks compared with 14 seniors who just did stretching and toning exercises for the same amount of time．
So，even going for a walk every 2 or 3 days forjust 10 to 45 minutes can help．That should be good news for your grandparents．
The effects of exercising on the brains of younger people haven't been studied yet．Still，it can't hurt to take occasional study breaks and go for a walk or run around with your friends．You might even do better in school．
Whatever you do，though，don't try to read and walk at the same time．You could end up hurting yourseff!
31．Walking regularly helps elderly people_______．
A．lose weight
B．become happier
C．concentrate better
D．look younger
32．After taking exercise for a few weeks，the mice were found to have_____．
A．higher blood pressure
B．faster heartbeat
C．more blood flow to the brain
D．better appearance
33．The first study on 41 elderly people found______．
A．the less-fit participants did arrow tasks faster
B．the fitter participants did arrow tasks faster
C．the less-fit participants gave more accurate answers
，2010年全国职称英语理工类（B级）考试真题及答案