2014届高三英语二轮【完形填空突破-3真2模含解析】19
【2012届甘肃省高三第一次诊断性考试】
完形填空（共20小题；每小题1.5分，满分30分）
阅读下面短文，从短文后所给各题的四个选项（A、B、C和D）中，选出可以填入空白处的最佳选项，并在答题卡上将该项涂黑。
Man - made causes probably do the most damage．There are many man-made causes． 21 is one of the biggest man-made problems．Pollution 22 in many shapes and sizes．Burning fossil（化石） fuels is one thing that causes pollution．Fossil fuels are fuels made of organic matter such as coal or oil．When fossil fuels are burned, they 23 a green house gas called CO2．Also mining coal and oil allows methane（甲烷）to escape．How does it escape? Methane is 24 in the ground． 25 coal or oil is mined, you have to dig up the earth a little．When you dig up the fossil fuels, you dig up the methane as well．
Another major man-made 26 of global warming is population．More people 27 ．Now you are probably thinking, "Wait a minute．You said agriculture will be damaged by more food, and more transportation, right? That means more methane because 28 will be more burning of fossil fuels, 29 more agriculture
