Australian scientists are trying to give kangaroo-style stomachs to cattle and sheep in order to cut the greenhouse gases they send out，which is thought to be responsible for global warming．

Thanks to special bacteria in the stomachs，kangaroo flatulence（肠胃气胀）contains no methane（甲烷）and scientists want to transfer that bacteria to cattle and sheep which produce large quantities of the harmful gas．

While the usual image of greenhouse gas pollution is a huge factory chimney pushing out carbon dioxide，farm animals’ passing wind contributes to a surprisingly high percentage of total emission（排放物）in some countries．

“Fourteen percent of emissions from all sources in Australia is from 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 are actually up around 50 percent，”he said．

Researchers say the bacteria also make 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．And about twenty percent of health-conscious Australians are believed to eat the national symbol already．

“It’s low in fat，it’s got high protein levels and it’s very clean in the sense that basically it’s the free-range（放养的）animal，”said Peter Ampt of the University of New South Wales’s institute of environmental studies．

小题1:The passage mainly talks about ________.

A．a better way to prevent air pollution

B．the danger of methane from farm animals

C．possible solutions to protecting environment

D．a recent research on global warming小题2: Scientists intend to put the bacteria into cattle and sheep in order to ________.

A．prevent them from sending out harmful gases

B．promote Australian farming

C．protect Australian ecosystem

D．make the most of the special bacteria小题3:Another possible solution to the problem is ________.

A．to reduce the number of animals raised on farms

B．to eat more kangaroos rather than keep more sheep and cattle

C．to eat more plants rather than beef and mutton

D．to grow more trees to absorb carbon dioxide小题4:From the passage we learn that ________.

A．it is easy to transfer the bacteria to cattle and sheep

B．farm animals are to blame for global warming in some countries

C．cattle and sheep produce more methane than kangaroos

D．less cattle and sheep are raised in New Zealand