单选题Machines are designed to help restore our Uintrinsic/U system of checks and balances of our biology.

单选题According to the last paragraph, man could not fly with flapping-wing flying machines because

单选题Electric Backpack Backpacks are convenient. They can hold your books, your lunch, and a change of clothes leaving your hands free to do other things. Someday, if you don't mind carrying a heavy load, your backpacks might also power your MP3 player, keep your cell phone running, and maybe even light your way home. Lawrence C. Rome and his colleagues from the University of Pennsylvania in Philadelphia and the Marine Biological Laboratory in WoodsHole, Mass. have invented a backpack that makes electricity from energy produced while its wearer walks. In military actions search-and-rescue operations and scientific field studies, people rely increasingly on cell phones global positioning system (GPS) receivers, night-vision goggles, and other battery powered devices to get around and do their work. The backpack's electricity-generating feature could dramatically reduce the amount of a wearer's load now devoted to spare batteries, report Rome and his colleagues in the Sept.9 science. The backpack's electricity-creating powers depend on springs used to hang a cloth pack from its metal frame. The frame sits against the wearer's back, and the whole pack moves up and down as the person walks. A gear mechanism converts vertical movements of the pack to rotary motions of an electrical generator, producing up to 7.4 watts. Unexpectedly, tests showed that wearers of the new backpack alter their gaits in response to the pack's oscillations, so that they carry loads more comfortably and with less effort than they do ordinary backpacks. Because of that surprising advantage, Rome plans to commercialize both electric and non-electric versions of the backpack. The backpack could be especially useful for soldiers, scientists, mountaineers, and emergency workers who typically carry heavy backpacks. For the rest of us, power-generating backpacks could make it possible to walk, play video games, watch TV, and listen to music, all at the same time. Electricity-generating packs aren't on the market yet, but if you do get one eventually just make sure to look both ways before crossing the street!

单选题Car Thieves Could Be Stopped Remotely Speeding off in a stolen car, the thief thinks he has got a great catch. But he is in a nasty surprise. The car is fitted with a remote immobilizer (使车辆不能调动的装置), and a radio signal from a control center miles away will ensure that once the thief switches the engine (51) , he will not be able to start it again. For now, such devices (52) only available for fleets of trucks and specialist vehicles used on construction sites. But remote immobilization technology could soon start to trickle down to ordinary cars and (53) be available to ordinary cars in the UK (54) two months. The idea goes like this. A control box fitted to the car incorporates (55) miniature cellphone, a microprocessor and memory, and a GPS satellite positioning receiver. (56) the car is stolen, a coded cellphone signal will tell the unit to block the vehicle's engine management system and prevent the engine (57) restarted. There are even plans for immobilizers (58) shut down vehicles on the move, though there are fears over the safety implications of such a system. In the UK an array of technical fixes is already making (59) harder for car thieves. "The pattern of vehicles crime has changed, "says Martyn Randall of Thatcham a security research organization based in Berkshire that is funded in part (60) the motor insurance industry. He says it would only take him a few minutes to (61) a novice how to steal a car, using a bare minimum of tools. But only if the car is more than 10 years old. Modem cars are a far tougher proposition, as their engine management computer will not (62) them to start unless they receive a unique ID code beamed out by the ignition key. In the UK, technologies like this (63) achieve a 31 percent drop in vehicle-related crime since 1997. But determined criminals ore still managing to find other ways to steal cars. Often by getting hold of the owner's keys in a burglary. In 2000, 12 percent of vehicles stolen in the UK were taken using the owner's keys double the previous year's figure. Remote-controlled immobilization system would (64) a major new obstacle in the criminal's way by making such thefts pointless. A group that includes Thatcham, the police, insurance companies and security technology firms have developed standards for a system that could go on the market sooner than the (65) expects.

单选题John is collaborating with mary in writing an article. A. cooperating B. competing C. combining D. arguing

单选题They have built canals to irrigate the desert.

单选题He said some harsh words about his brother.

单选题After what I have heard, I have no Uinclination/U to go to her home.

单选题A local hypnotist (催眠师) offered his services, and Edgar readily accepted.

单选题They have given up the hope to save their friend from drowning. A. ended B. abandoned C. built D. strengthen

单选题This poem {{U}}depicts{{/U}} the beautiful scenery of a town in the South. A. praises B. writes C. describes D. Imitates

单选题All those present noticed the minute change in his look.A. bigB. timelyC. dramaticD. slight

单选题Hair Care Whether the hair is long or short, it must be regularly brushed and regularly washed. For greasy(油性的) hair, especially if the owner lives in a town, it may be necessary to wash the head every four to five days. Those with a dry hair can usually go a little longer, but this is a matter for the individual to decide. As for style, this must be studied according to what is the latest fashion and also to suit the individual at different times of her life. If a woman is not able to go to hairdresser very often, it is important that she chooses a style she can easily manage for herself, and this nearly always means that the first cut must be very standard. The same applies to permanent waving (烫发). I think that this should be carried out three or four times a year, so that the hair never gets out of hand. One thing would be remembered though, that is, whatever you apply to the head can have some effect upon the skin and therefore anything strong should be used with care. Or you may use milder products. Young people who has spots or skin troubles on their face should take particular care to ensure that the hair is both clean and does not come into contact with the affected piece of skin. Hair is very difficult to keep completely clean and therefore anyone running their hands through their hair and afterwards touching their face, or letting their hair fall over their faces, might spread infection from one place to another. Good hair does a lot to the effect of a face, so if you want to look charming, please start with your hair.

单选题The bad news {{U}}upset{{/U}} me very much.

单选题This reminds me of {{U}}lots of{{/U}} things. A. much B. some C. big D. many

单选题Mint. com has benefited from a cultural shift as well as a tectmological one. During the free-spending housing bubble, a Web site that encouraged people to manage spending, comparison, shop, and save was definitely out of step with the prevailing mood. But once the financial and housing markets tanked and the nation" went into recession, the zeitgeist (时代精神) shifted. Shrinking top lines have caused people to focus on the bottom line, and the savings rate has spiked. Third homes and luxury goods are out; coupons (优惠券) and growing your own vegetables are in. Saving is the new borrowing. Thus considered, Mint. corn, which launched in September 2007, timed the market perfectly. It hit the Web at a time when more Americans suddenly had the time, inclination, and motivation to manage their financial affairs more prudently. And it gave them a way to do it without having to spend a dime. What is the main reason that mint. com is successful?A. it offers free service.B. It came into the market at a perfect time.C. It meets people's expectations of websites.D. It catered to people's interest in planting vegetables.

单选题Mother Nature Shows Her Strength Tornadoes (龙卷风) and heavy thunderstorms moved across the Great Lakes and into Trumbull County on Saturday evening. The storms were dramatic and dangerous. George Snyder was driving the fire truck down Route 88 when he first noticed that a funnel (漏斗状的) cloud was behind him. "I stopped the truck and watched the funnel cloud. It was about 100 feet off the ground and I saw it go up and down for a while. It was moving toward Bradley Road and then suddenly it disappeared," Snyder said. Snyder only saw one of the funnel clouds that passed through northeastern Ohio on Saturday. In Trumbull County, a tornado turned trees onto their sides. Some trees fell onto houses and cars. Other trees fell into telephone and electrical wires as they went down. Amanda Symcheck was having a party when the storm began. "I knew something was wrong," she said. "I saw the sky go green and pink (粉红色). Then it sounded like a train rushing toward the house. I started crying and told everyone to go to the basement for protection. " The tornado caused a lot of damage to cars and houses in the area. It will take a long time and much money to repair everything. There was also serious water damage from the thunderstorms. The heavy rains and high wind caused the power to go out in many homes. The storms caused serious flooding in areas near the river. More than four inches of rain fell in parts of Trumbull County. The river was so high that the water ran into streets and houses. Many streets had to be closed to cars and trucks because of the high water. This made it difficult for fire trucks, police cars, and other rescue vehicles to help people who were in trouble. Many people who live near the river had to leave their homes for their own safety. Some people reported five feet of water in their homes, Local and state officials opened emergency shelters for the people who were evacuated (撤走), The Red Cross served meals to them. "This was a really intense storm," said Snyder. "People were afraid. Mother Nature can be fierce. We were lucky this time. No one was killed. /

单选题阅读下面的短文，文中有15处空白，每处空白给出了4个选项，请根据短文的内容从4个选项中选择1个最佳答案。 {{B}}An Intelligent Car{{/B}} Driving needs sharp eyes, keen ears, quick brain, and coordination between hands and the brain. Many human drivers have all{{U}} (51) {{/U}}and can control a fast-moving car. But how does an intelligent car control itself? There is a virtual driver in the smart car. This virtual driver has "eyes", "brains", "hands" and "feet", too. The minicameras {{U}}(52) {{/U}} each side of the car are his "eyes", which observe the road conditions ahead of it. They watch the{{U}} (53) {{/U}}to the car's left and right. There is also a highly{{U}} (54) {{/U}}driving system in the car. It is the built-in computer, which is the virtual driver's "brain". His "brain" calculates the speeds of{{U}} (55) {{/U}}moving cars near it and analyzes their positions. Basing on this information, it chooses the right {{U}}(56) {{/U}}for the intelligent car, and gives{{U}} (57) {{/U}}to the "hands" and "feet" to act accordingly. In this way, the virtual driver controls his car. What is the virtual driver's best advantage? He reacts {{U}}(58) {{/U}}. The minicameras are {{U}}(59) {{/U}} images continuously to the "brain." It {{U}}(60) {{/U}} the processing of the images within 100 milliseconds. However, the world's best driver {{U}}(61) {{/U}} needs one second to react. {{U}}(62) {{/U}}, when he takes action, he needs one more second. The virtual driver is really wonderful. He can reduce the accident {{U}}(63) {{/U}} considerably on expressways. In this case, can we let him have the wheel at any time and in any place? Experts {{U}}(64) {{/U}} that we cannot do that just yet. His ability to recognize things is still {{U}}(65) {{/U}} He can now only drive an intelligent car on expressways.

单选题At present about 10% of American citizens possess a microcomputer.

单选题Some professional footballers Uearn/U more in a month than many of us do in many years.