Read the following article and select the best answer. Article: Scientists have always been interested in the high level of organization in ant societies. American researchers have watched ants build life-saving rafts to keep afloat during floods. They also have documented how ant colonies choose their next queen--the female whose job is to produce eggs rather than seek food for others. New technology is helping to improve researchers' understanding of the insects. But there is still a lot to be learned. Fire ants living in Brazilian forests are perfectly at home in an environment where flooding is common. To save themselves, the insects connect their legs together and create floating rafts. Some ant rafts can be up to 20 centimeters wide. David Hu who is a mechanical engineer with the Georgia Institute of Technology, also known as Georgia Tech, says, "If you have 100 ants, which means 600 legs, 99 percent of those legs will be connected to a neighbor. So they're very, very good at maintaining this network." David Hu and other Georgia Tech researchers want to study ants and the secret of their engineering. They freeze ant rafts and then look at them with the help of computed technology, or CT, images. The pictures show that larger ants serve in central positions to which smaller ants hold. The larger ants form pockets of air that keep the insects afloat. Scientists say small robots or materials that can change shape could be programmed in a similar way, working towards a shared goal. Researchers at North Carolina State University are also studying ants. They examined how Indian jumping ants choose the leader of the colony when they lose their top female or queen. Question: What will probably be talked about in the following part? - How ants work in their societies. - How ants choose their leader. - How ants memorize the dead. - How ants escape from the flood.
How ants choose their leader.

Read the following article and select the best answer. Article: Cities need to put efforts to deal with pollution and clear the air. Chinese cities will need to put efforts to clear up the sky when a new department to improve regional air quality is set up by 2015, according to the latest plan released by the State Council. Besides the existing pollution control program for SO2, regional emission caps for other certain chemicals will be established in the three key air polluting areas-- the Yangtze River Delta, Pearl River Delta and the Beijing-Tianjin-Hebei region. Coal-consumption caps will also be tried out in some areas, according to the plan. "The plan is aimed at dealing with regional air pollution--such as acid rain and smog--which have become increasingly obvious in China in recent years and caused a severe threat to people's health," Zhang Lijun, vice-minister of environmental protection, said in an interview on Monday. "The air quality in a city affects the regions nearby because pollutants Can travel through the atmosphere," said Chai Fahe, vice-director of Chinese Research Academy of Environmental Sciences. "So efforts to reduce air pollution in a single city, targeting a certain pollutant will not be enough," Chai said. Zhang said, "The country's major industrial districts--the Yangtze River Delta, Pearl River Delta and the Beijing-Tianjin-Hebei region--have recorded more than 100 misty days annually in recent years." These three regions, home to at least 200 million people, occupy only 6. 3 percent of the country's area but consume 40 percent of the country's coal and produce half of its steel, according to official figures. Studies also show that the visibility in eastern regions of China has dropped by 7 to 15 km compared to that in the early 1960s, as a result of air pollution. Liaoning province, the Shandong Peninsula, Wuhan in Hubei province and its surrounding area, the Changsha-Zhuzhou-Xiangtan region in Hunan province, the Chengdu-Chongqing region, and the western coast of the Taiwan Straits are also listed as areas to carry out such regional... Question: It will not be enough to reduce air pollution in a single city because _ . - air pollution has been becoming more and more serious in recent years - air pollution like acid rain and smog is threatening people's health - air pollutants in a city can travel in the sky and affect nearby areas - air pollutants stay in fixed places over the cities
air pollutants in a city can travel in the sky and affect nearby areas

Q: Read the following article and select the best answer. Article: After lunch,I walked back home. I was just to cross the street when I heard the sound of a coin dropping. It wasn't much but,as I turned, my eyes caught the heads of several other people turning too. A woman had dropped what appeared to be a dime. The tinkling sound of a coin dropping on pavement is an attention-getter.It Can be nothing more than a penny.Whatever the coin is,no one ignores the sound of it.It got me thinking about sounds again.We are surrounded by so many sounds that attract the most attention. People in New York City seldom turn to look when a fire engine,a police car or an ambulance comes screaming along the street.When I'm in New York,I'm a New Yorker.I don't turn either.Like the natives,I hardly hear a siren there. However,at home in my little town in Connecticut,it's different.The distant sound of a police car, all emergency vehicle or a fire siren brings me to my feet if I'm seated and brings me to the window if I'm in bed.It's the quietest sounds that have most effect on us.not the loudest.In the middle of the night, I can hear a dripping tap a hundred yards away thigh three closed doors.I've been hearing little creaking noises and sounds which my imaginnation turns into footsteps in the middle of the night for twenty-five years in our house.How come I never hear those sounds in the daytime? I'm quite clear in my mind what the good sounds are and what the bad sounds are,I've turned against whistling,for instance:I used to think of it as the mark of a happy worker but lately I've been associating the whistler with a nervous person making unconscious noises.The tapping,tapping,tapping of my typewriter as the keys hit the paper is a lovely sound to me.I often like the sound of what I write better than the looks of it. Question: How does the author feel about sounds in general? - They make him feel al home. - He thinks they should be ignored - He prefers silence to loud noises. - He believes they are part of our life
A: He believes they are part of our life

Q: Read the following article and select the best answer. Article: Time Zones Strange things happen to time when you travel. Because the earth is divided into twenty-four zones one hour apart .You can have days with more or fewer than twenty-four hours, and weeks more or fewer than seven days. If you make a five-day trip across the Atlantic Ocean ,your ship enters a different time zone every day. As you enter each zone, the time changes one hour. Travelling west ,you set your clock back; traveling east , you set it ahead. Each day of your trip has either twenty-five or twenty-three hours. If you travel by ship across the Pacific , you cross the international date line. By agreement, this is the point where a new day begins, when you cross the line, you change your calendar one full time day, backward or forward. Travelling east, today becomes yesterday; traveling west, it is tomorrow. Question: Strange things happen to time when you travel because _ . - no day really has 24 hours - the earth is divided into time zones - time zones are not all the same size - no one knows where time zones are
A: the earth is divided into time zones