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2017届高考英语二轮专题复习精品之 阅读理解 Australian scientists are trying to give kangaroo-style stomachs to cattle and sheep in a bid to cut the emission of greenhouse gases blamed for global warming. Thanks to special bacteria in their stomachs, kangaroo farts contain no methane（甲烷）and scientists want to transfer that bacteria to cattle and sheep who emit large quantities of the harmful gas. While the usual image of greenhouse gas pollution is a billowing smokestack pushing out carbon dioxide, livestock passing wind contribute a surprisingly high percentage of total emissions in some countries. "Fourteen percent of emissions from all sources in Australia is from enteric methane from cattle and sheep," said Athol Klieve, a senior research scientist with the Queensland state government. "And if you look at another country such as New Zealand, which has got a much higher agricultural base, they're actually up around 50 percent," he said. Researchers say the bacteria also makes the digestive process much more efficient and could potentially save millions of dollars in feed costs for farmers. But it will take researchers at least three years to isolate the bacteria, before they can even start to develop a way of transferring it to cattle and sheep. Another group of scientists, meanwhile, has suggested Australians should farm fewer cattle and sheep and just eat more kangaroos. | 
