On a Saturday morning earlier this September, the world got its first look at the Strati. This electric vehicle is unlike any other currently on the road. It rolls on four wheels, but its body and chassis(底盘) weren’t built in a factory. Instead, Strati’s designers used a technology called 3-D printing. It created those parts of the car in one piece, from the ground up. “Compared to a typical vehicle on the road, the Strati definitely looks different,” says Greg Schroeder, a senior research engineer at the Center for Automotive Research in Ann Arbor, Mich. He did not work on the new car. His organization studies trends and changes in the auto industry. It took 44 hours to print the new car at the International Manufacturing Technology Show in Chicago. Over the next few days, the car’s designers installed additional parts. These included the car’s engine, brakes and tires. Then, early on September 13, Jay Rogers climbed into the car, started its engine and drove the vehicle onto the street. Rogers helped found Local Motors. It’s the Arizona-based company behind the Strati. Two weeks later, his team printed a second Strati, and just as fast, at a fair in New York City. Justin Fishkin, a local Motors official, sees the Strati as a window into the future. Today, car buyers are limited in their choice of a vehicle. They can order only what car companies have already designed. But in the future, he says, you may be able to design your own car online and then get it printed to order. Manufacturing experts say 3-D printing has begun to revolutionize how they make things. The technology has been around for decades. But these machines used to be so expensive that only large companies could afford them. In the last few years, though, that has changed. Many of the machines are now inexpensive enough for small companies—or even individuals —to own. Some local libraries make them available to the public. High Schools are beginning to use them in classrooms. Wide access to these printers means people can now design and print a wide variety of new things. The car’s printer is a one-of-a-kind device. The technology behind the 3-D printer used in Chicago is an example of additive manufacturing. This process builds solid objects, slice by slice, from the bottom up. (“Strati” means layers, in Italian.) A mechanical arm moves a nozzle from one side to another, back and forth. As it moves, the nozzle deposits a liquid—often melted plastic or metal (but it could be food, concrete or even cells) —that quickly hardens or bonds to become solid or semi-solid. This creates a single, thin layer. Once a layer is complete, the printer starts depositing the next one. “There’s a lot of interest in 3-D printing in the auto industry,” says Schroeder. Right now, the technology is particularly useful for building models of cars or car parts. To compete with current auto manufacturers, the 3-D printer would have to increase in a hurry, Schroeder says. By contrast, he notes, a Ford F-150 pickup truck rolls off an assembly line at a rate of roughly one per minute. To print as many Stratis would require many more printers. Schroeder says he doesn’t see 3-D printing soon taking over for such high-volume manufacturing. But, he adds, “Who knows what will happen in the long term?” Scientists at Oak Ridge National Laboratory in Tennessee designed the 3-D printer used in Chicago. Lonnie Love, a research scientist at the lab, led the effort. Additive manufacturing often is slow and expensive. It also may produce materials that are unreliable, Love says. So for two years, his team searched for ways to make 3-D printing better. They built new machines and tested them over and over. All of that work paid off: their new machine is fast and uses less expensive material than earlier printers. In addition, it prints a plastic embedded with fibers of carbon to produce a stronger material. This helps ensure the material won’t crack or break under pressure. 【小题1】Which of the following statements about the first Strati is TRUE? A．It was born in a car factory in Chicago. B．All parts of it were not made by using a technology called 3-D technology. C．It is a pity that it has not run on the street so far. D．Many senior research engineers worked on it, including Greg Schroeder. 【小题2】What can we infer from Paragraph 5? A．Large companies are always rich enough to buy expensive things. B．Now High Schools are beginning to use 3-D printers in classrooms. C．Wide access to 3-D printers has made it possible for people to order novel things online. D．High prices of new products can stop them from being used widely in the beginning. 【小题3】What does the word “nozzle” in Paragraph 7 possibly refer to? A．A single, thin layer. B．A part of the 3-D printer. C．A solid or semi-solid object. D．A person who operates the machine. 【小题4】Why did Lonnie Love make efforts to improve 3-D printing with his team? A．Because additive manufacturing might produce unreliable materials. B．Because he just was interested in making new things. C．Because he just wanted to build new machines and test them D．Because additive manufacturing is always slow but inexpensive. 【小题5】Which of the following can be the best title for this passage? A．3-D Printers Are Coming B．3-D Printers Are Becoming Well- Known C．3-D Printers Are Becoming Cheaper D．3-D Printers Are Making Cars

How Ozone Pollution Works Introduction to How Ozone Pollution Works The weather report on the radio or TV tells you that it is going to be sunny and hot and that an orange ozone alert has been issued. What is ozone What does an orange alert mean Why should you be concerned about it In this article, we will examine what ozone is, how it is produced, what health hazards it poses and what you can do to reduce ozone pollution. Ozone is a molecule of three oxygen atoms bound together (O3). It is unstable and highly reactive. Ozone is used as a bleach, a deodorizing agent, and a sterilization agent for air and drinking water. At low concentrations, it is toxic. Ozone is found naturally in small concentrations in the stratosphere, a layer of Earth’s upper atmosphere. In this upper atmosphere, ozone is made when ultraviolet light from the sun splits an oxygen molecule (O2), forming two single oxygen atoms. If a freed atom collides with an oxogen molecule, it becomes ozone. Stratospheric ozone has been called "good" ozone because it protects the Earth’s surface from dangerous ultraviolet light. Ozone can also be found in the troposphere, the lowest layer of the atmosphere. Tropospheric ozone (often termed "bad" ozone) is man-made, a result of air pollution from internal combustion engines and power plants. Automobile exhaust and industrial emissions release a family of nitrogen oxide gases (NOx) and volatile organic compounds (VOC), by-products of burning gasoline and coal. NOx and VOC combine chemically with oxygen to form ozone during sunny, high-temperature conditions of late spring, summer and early fall. High levels of ozone are usually formed in the heat of the afternoon and early evening, dissipating during the cooler nights. Although ozone pollution is formed mainly in urban and suburban areas, it ends up in rural areas as well, carried by prevailing winds or resulting from cars and trucks that travel into rural areas. Significant levels of ozone pollution can be detected in rural areas as far as 250 miles ( 150 km) downwind from urban industrial zones. Make Your Own Ozone Detector You can make ozone test strips to detect and monitor ozone levels in your own backyard or around your school. You will need: ・cornstarch ・filter paper (coffee filters work well) ・potassium iodide (can be ordered from a science education supplier such as Carolina Biological Supply or Fisher Scientific ) Basically, you make a paste from water, corn starch and potassium-iodide, and you paint this paste on strips of filter paper. You then expose the strips to the air for eight hours. Ozone in the air will react with the potassium iodide to change the color of the strip. You will also need to know the relative humidity, which you can get from a newspaper, weather broadcast or home weather station. Avoiding and Reducing Ozone When you inhale ozone, it travels throughout your respiratory tract. Because ozone is very corrosive, it damages the bronchioles and alveoli in your lungs, air sacs that are important for gas exchange. Repeated exposure to ozone can inflame lung tissues and cause respiratory infections. Ozone exposure can aggravate existing respiratory conditions such as asthma, reduce your lung function and capacity for exercise and cause chest pains and coughing. Young children, adults who are active outdoors and people with respiratory diseases are most susceptible to the high levels of ozone encountered during the summer. In addition to effects on humans, the corrosive nature of ozone can damage plants and trees. High levels of ozone can destroy agricultural crops and forest vegetation. Avoiding Ozone Exposure To protect yourself from ozone exposure, you should be aware of the Air Quality Index (AQI) in your area everyday--you can usually find it in the newspaper or on a morning weather forecast on TV or radio. You should also be familiar with the U.S. Environmental Protection Agency (EPA) guide for ozone-alert values. What do the numbers in the AQI mean The AQI measures concentrations of five air pollutants: ozone, sulfur dioxide, particulate matter, carbon monoxide and nitrogen dioxide. The EPA has chosen these pollutants as criteria pollutants, but these are not all of the pollutants in the air. These concentrations are compared to a standard set out in federal law. An index value of 100 means that all of the criteria pollutants are at the maximum level that is considered safe for the majority of the population. To reduce your exposure to ozone, you should avoid exercising during afternoon and early evening hours in the summer. Reducing Ozone Pollution There are several ways you can help to decrease ozone pollution: ・Limit using your automobile during afternoon and early evening hours in the late spring, summer and early fall. ・Do not use gasoline-powered lawn equipment during these times. ・Do not fuel your car during these times. ・Do not light fires or outdoor grills during these times. ・Keep the engine of your car or boat tuned, ・Make sure that your tires are properly inflated. ・Use environmentally safe paints, cleaning and office products (some of these chemicals are sources of VOC). ・Conserve energy. Besides personal attempts to reduce ozone pollution, the EPA has initiated more stringent air-quality standards (such as the Clean Air Act and its modifications) to reduce air pollution. Compliance with these standards by industries, manufacturers and state and local governments has significantly reduced the levels of many common air pollutants. With continued conservation and reduction practices, adherence to ozone- pollution warnings, research and government regulation, ozone-pollution levels should continue to fall. Perhaps future generations will not be threatened by this environmental pollutant. How can ozone be both good and bad The thing that determines whether ozone is good or bad is its location. Ozone is "good" when it is in the stratosphere. The stratosphere is a layer of the atmosphere starting at the level of about 6 miles (about 10 kilometers) above sea level. The stratosphere naturally contains about six parts per million of ozone, and this ozone is very beneficial because it absorbs UV radiation and prevents it from reaching us. Ozone is "bad" when it is at ground level. Ozone is a very reactive gas that is hard on lung tissue. It also damages plants and buildings. Any ozone at ground level is a problem. Unfortunately, chemicals in car exhaust and chemicals produced by some industries react with light to produce lots of ozone at ground level. In cities, the ozone level can rise to a point where it becomes hazardous to our health. That’s when you hear about an ozone warning on the news.What is not mentioned as a way that helps to decrease ozone pollution A．Do not light fires or outdoor grills during afternoon and early evening hours in the late spring, summer and early fall.B．Ride bicycles, dim the lights, and take fewer showers.C．Do not fuel your car during afternoon and early evening hours in the late spring, summer and early fall.D．Make sure that your tires are properly inflate

Rob took Trina out for lunch in ______ for fixing his computer. ()A. novelB. spoilC. acceptableD. exchange

The second half of his voyage was by far the more dangerous part ______ he sailed round the treacherous Cape Horn.A. whereB. of whichC. during whichD. that

1-|||-2,-|||-One day,late in the autumn,my master had-|||-to go a long journey on business.I was put into 1114017-|||-tan theta dog-cart (单马拉双轮马车),and John went-|||-with his master.I always liked to go in the dog--|||-cart,it was so light,and the high wheels ran along-|||-so pleasantly. There had been a great deal of rain,-|||-and now the wind was very high and blew the-|||-dry leaves across the road in a shower ①We went-|||-merrily along till we came to the toll-bar and the-|||-low wooden bridge.The river banks were rather-|||-high,and the bridge,instead of rising,went across-|||-just level,so that in the middle,if the river was-|||-full,the water would be nearly up to the woodwork-|||-and thick wooden board; but as there were strong-|||-rails on each side,people did not mind it.-|||-The man at the gate said the river was rising fast,and he feared it would be a bad-|||-night.Many of the grasslands were under water, and in one low part of the road the-|||-water was half-way up to my knees; the bottom was good,and master drove gently,so-|||-it did not matter.-|||-When we got to the town,of course I had a good feed; but as the master`s business-|||-engaged him a long time,we did not start for home till rather late in the afternoon.The-|||-wind was then much higher, and I heard the master say to John he had never been out in-|||-such a storm;and so I thought,as we went along the skirts of a wood, where the great1-|||-2,-|||-One day,late in the autumn,my master had-|||-to go a long journey on business.I was put into 1114017-|||-tan theta dog-cart (单马拉双轮马车),and John went-|||-with his master.I always liked to go in the dog--|||-cart,it was so light,and the high wheels ran along-|||-so pleasantly. There had been a great deal of rain,-|||-and now the wind was very high and blew the-|||-dry leaves across the road in a shower ①We went-|||-merrily along till we came to the toll-bar and the-|||-low wooden bridge.The river banks were rather-|||-high,and the bridge,instead of rising,went across-|||-just level,so that in the middle,if the river was-|||-full,the water would be nearly up to the woodwork-|||-and thick wooden board; but as there were strong-|||-rails on each side,people did not mind it.-|||-The man at the gate said the river was rising fast,and he feared it would be a bad-|||-night.Many of the grasslands were under water, and in one low part of the road the-|||-water was half-way up to my knees; the bottom was good,and master drove gently,so-|||-it did not matter.-|||-When we got to the town,of course I had a good feed; but as the master`s business-|||-engaged him a long time,we did not start for home till rather late in the afternoon.The-|||-wind was then much higher, and I heard the master say to John he had never been out in-|||-such a storm;and so I thought,as we went along the skirts of a wood, where the great1-|||-2,-|||-One day,late in the autumn,my master had-|||-to go a long journey on business.I was put into 1114017-|||-tan theta dog-cart (单马拉双轮马车),and John went-|||-with his master.I always liked to go in the dog--|||-cart,it was so light,and the high wheels ran along-|||-so pleasantly. There had been a great deal of rain,-|||-and now the wind was very high and blew the-|||-dry leaves across the road in a shower ①We went-|||-merrily along till we came to the toll-bar and the-|||-low wooden bridge.The river banks were rather-|||-high,and the bridge,instead of rising,went across-|||-just level,so that in the middle,if the river was-|||-full,the water would be nearly up to the woodwork-|||-and thick wooden board; but as there were strong-|||-rails on each side,people did not mind it.-|||-The man at the gate said the river was rising fast,and he feared it would be a bad-|||-night.Many of the grasslands were under water, and in one low part of the road the-|||-water was half-way up to my knees; the bottom was good,and master drove gently,so-|||-it did not matter.-|||-When we got to the town,of course I had a good feed; but as the master`s business-|||-engaged him a long time,we did not start for home till rather late in the afternoon.The-|||-wind was then much higher, and I heard the master say to John he had never been out in-|||-such a storm;and so I thought,as we went along the skirts of a wood, where the great1-|||-2,-|||-One day,late in the autumn,my master had-|||-to go a long journey on business.I was put into 1114017-|||-tan theta dog-cart (单马拉双轮马车),and John went-|||-with his master.I always liked to go in the dog--|||-cart,it was so light,and the high wheels ran along-|||-so pleasantly. There had been a great deal of rain,-|||-and now the wind was very high and blew the-|||-dry leaves across the road in a shower ①We went-|||-merrily along till we came to the toll-bar and the-|||-low wooden bridge.The river banks were rather-|||-high,and the bridge,instead of rising,went across-|||-just level,so that in the middle,if the river was-|||-full,the water would be nearly up to the woodwork-|||-and thick wooden board; but as there were strong-|||-rails on each side,people did not mind it.-|||-The man at the gate said the river was rising fast,and he feared it would be a bad-|||-night.Many of the grasslands were under water, and in one low part of the road the-|||-water was half-way up to my knees; the bottom was good,and master drove gently,so-|||-it did not matter.-|||-When we got to the town,of course I had a good feed; but as the master`s business-|||-engaged him a long time,we did not start for home till rather late in the afternoon.The-|||-wind was then much higher, and I heard the master say to John he had never been out in-|||-such a storm;and so I thought,as we went along the skirts of a wood, where the great1-|||-2,-|||-One day,late in the autumn,my master had-|||-to go a long journey on business.I was put into 1114017-|||-tan theta dog-cart (单马拉双轮马车),and John went-|||-with his master.I always liked to go in the dog--|||-cart,it was so light,and the high wheels ran along-|||-so pleasantly. There had been a great deal of rain,-|||-and now the wind was very high and blew the-|||-dry leaves across the road in a shower ①We went-|||-merrily along till we came to the toll-bar and the-|||-low wooden bridge.The river banks were rather-|||-high,and the bridge,instead of rising,went across-|||-just level,so that in the middle,if the river was-|||-full,the water would be nearly up to the woodwork-|||-and thick wooden board; but as there were strong-|||-rails on each side,people did not mind it.-|||-The man at the gate said the river was rising fast,and he feared it would be a bad-|||-night.Many of the grasslands were under water, and in one low part of the road the-|||-water was half-way up to my knees; the bottom was good,and master drove gently,so-|||-it did not matter.-|||-When we got to the town,of course I had a good feed; but as the master`s business-|||-engaged him a long time,we did not start for home till rather late in the afternoon.The-|||-wind was then much higher, and I heard the master say to John he had never been out in-|||-such a storm;and so I thought,as we went along the skirts of a wood, where the great

The period _________ people learned to melt iron is called the Iron Age.A. whenB. thatC. during whichD. what

Mountains rise straight up,creating the only beauty. Bike paths take you past the-|||-villages and farms.Enjoy this beautiful views from your bike,or stop and talk with one-|||-of the villagers working in his field.-|||-Adventure advice:When your feet are tired,take a boat trip along the beautiful and-|||-famous Li River.-|||-White-water rafting in Nepal-|||-In Nepal,you can experience thrilling rapids(湍流)and the beauty of the-|||-Himalayas at the same time. Take a white-water rafting trip down the Sun Koki River,-|||-world-renowned for its powerful rapids.At night you'll camp beside the river on white-|||-water,enjoy the quiet,lonely Nepalese countryside.-|||-Adventure advice:Don't go rafting in summer. High water levels make it-|||-dangerous.-|||-Scuba diving in Malaysia-|||-Go diving in the clear waters around Spaded,an island in Malaysia,and discover an-|||-underwater world.You'll see large sea animals swimming along.The colorful coral-|||-along the reefs hides tiny fish.The wide kind of tropical life found around Spaded makes-|||-it famous worldwide for diving.-|||-Adventure advice:You can dive at Spaded,but you can't sleep there.The island is-|||-a protected park,but you can stay on one of the nearby islands.-|||-Title: Three 1 Adventures-|||-Adventures 2-|||-3-|||-You can 4 a bike to travel around Guilin and enjoy When your feet are 5 _,take a-|||-the beautiful natural views. __ boat trip.-|||-You can experience thrilling rapids and the 6 of-|||-the Himalayas at the same time. You'd better not go rafting-|||-Nepal Take a white-water rafting trip down the Sun in 8 .-|||-8-|||-Kosi River-|||-At night you can go 7 beside the river.-|||- Go scuba diving in the clear waters around Spaded,a You can dive but can't 10 -|||-famous Island is famous for 9 . there.-|||-1 2 3 4 5-|||-6 7 8 9 10-|||-词汇自主拓展-|||-序号 单词/短语 词典例句-|||-1-|||-2-|||-3-|||-4-|||-5

34. Employees at all levels come together regularly, sometimes once a week, more often twice a month, to ________ the question: “What can we do to improve what we have already done?”A. pose B. address C. raise D. reckon

The police officer ordered the car to ________ at the intersection.A. gritB. haltC. dockD. default

mosequitoes comfortable stylish malaria designer wearable 1.I love to dress my dog in ______clothes.2.Expertssay the best way to prevent the diseases carried by_______ is not to be bitten by one.3.The reality is that complex ______computers still seem very far off from mass market consumption.4.The clothes were copycatted straight from ______originals.5fu.She leads a happy and ______life, never lacking for money or friends.6.______is a serious disease caried by mosquitoes, which causes periods of fever.