英语 热门试卷

B

Find Your Adventure at the Space and Aviation (航空)Center

    If you're looking for a unique adventure, the Space and Aviation Center(SAC)is the place to be. The Center offers programs designed to challenge and inspire with hands-on tasks and lots of fun.

    More than 750,000 have graduated from SAC, with many seeking employment in engineering, aviation, education, medicine and a wide variety of other professions. They come to camp, wanting to know what it is like to be an astronaut or a pilot, and they leave with real-world applications for what they're studying in the classroom.

    For the trainees，the programs also offer a great way

to earn merit badges(荣誉徽章). At Space Camp, trainees can earn their Space Exploration badge as they build and fire model rockets, learn about space tasks and try simulated (模拟) flying to space with the crew from all over the world. The Aviation Challenge program gives trainees the chance to earn their Aviation badge. They learn the principles of flight and test their operating skills in the cockpit(驾驶舱)of a variety of flight simulators. Trainees also get a good start on their Wilderness Survival badge as they learn about water-and

    land-survival through designed tasks and their search and rescue of “downed" pilot.

    With all the programs, teamwork is key as trainees learn the importance of leadership and being part of a bigger task.

    All this fun is available for ages 9 to 18. Families can enjoy the experience together, too, with Family Camp programs for families with children as young as 7.

    Stay an hour or stay a week--there is something here for everyone!

    For more details，please visit us online at www.oursac.com.

D

Preparing Cities for Robot Cars

    The possibility of self-driving robot cars has often seemed like a futurist's dream, years away from materializing in the real world. Well, the future is apparently now. The California Department of Motor Vehicles began giving permits in April for companies to test truly self-driving cars on public roads. The state also cleared the way for companies to sell or rent out self-driving cars, and for companies to operate driverless taxi services. California, it should be noted, isn't leading the way here. Companies have been testing their vehicles in cities across the country. It's hard to predict when driverless cars will be everywhere on our roads. But however long it takes, the technology has the potential to change our transportation systems and our cities, for better or for worse, depending on how the transformation is regulated.

    While much of the debate so far has been focused on the safety of driverless cars(and rightfully so), policymakers also should be talking about how self-driving vehicles can help reduce traffic jams, cut emissions(排放) and offer more convenient, affordable mobility options. The arrival of driverless vehicles is a chance to make sure that those vehicles are environmentally friendly and more shared.

    Do we want to copy- or even worsen- the traffic of today with driverless cars? Imagine a future where most adults own individual self-driving vehicles. They tolerate long, slow journeys to and from work on packed highways because they can work, entertain themselves or sleep on the ride, which encourages urban spread. They take their driverless car to an appointment and set the empty vehicle to circle the building to avoid paying for parking. Instead of walking a few blocks to pick up a child or the dry cleaning, they send the self-driving minibus. The convenience even leads fewer people to take public transport——an unwelcome side effect researchers have already found in ride- hailing(叫车) services.

    A study from the University of California at Davis suggested that replacing petrol-powered private cars worldwide with electric, self-driving and shared systems could reduce carbon emissions from transportation 80% and cut the cost of transportation infrastructure (基础设施) and operations40%by2050. Fewer emissions and cheaper travel sound pretty appealing. The first commercially available driverless cars will almost certainly be fielded by ride-hailing services, considering the cost of self-driving technology as well as liability and maintenance issues(责任与维护问题).But driverless car ownership could increase as the prices drop and more people become comfortable with the technology.

    Policymakers should start thinking now about how to make sure the appearance of driverless vehicles doesn't extend the worst aspects of the car-controlled transportation system we have today. The coming technological advancement presents a chance for cities and states to develop transportation systems designed to move more people，and more affordably. The car of the future is coming. We just have to plan for it.

第一节(共15小题:每小题2分,共30分)

    阅读下列短文,从每题所给的A、B、C、D四个选项中,选出最仁选项,并在答题卡上将该项涂黑。

A

My First Marathon(马拉松)

    A month before my first marathon, one of my ankles was injured and this meant not running for two weeks, leaving me only two weeks to train. Yet, I was determined to go ahead.

    I remember back to my 7th year in school. In my first P.E. class, the teacher required us to run laps and then hit a softball. I didn't do either well. He later informed me that I was“ not athletic”.

    The idea that I was "not athletic" stuck with me for years. When I started running in my 30s，I realized running was a battle against myself, not about competition or whether or not I was athletic. It was all about the battle against my own body and mind. A test of wills!

    The night before my marathon, I dreamt that I couldn't even find the finish line. I woke up sweating and nervous, but ready to prove something to myself.

    Shortly after crossing the start line, my shoe laces (鞋带)became untied. So I stopped to readjust. Not the start I wanted！

    At mile3, I passed a sign:“ GO FOR IT, RUNNERS!”

    By mile 17, I became out of breath and the once injured ankle hurt badly. Despite the pain, I stayed the course walking a bit and then running again.

    By mile 21, I was starving！

    As I approached mile 23, I could see my wife waving a sign. She is my biggest fan. She never minded the alarm clock sounding at 4 a.m. or questioned my expenses on running.

    I was one of the final runners to finish. But I finished! And I got a medal. In fact, I got the same medal as the one that the guy who came in first place had.

    Determined to be myself,, move forward, free of shame and worldly labels(世俗标签)， I can now call myself a "marathon winner”.

C

Plastic-Eating Worms

    Humans produce more than 300 million tons of plastic every year. Almost half of that winds up in landfills(垃圾填埋场)， and up to 12 million tons pollute the oceans. qSo far there is no effective way to get rid of it, but a new study suggests an answer may lie in the stomachs of some hungry worms.

    Researchers in Spain and England recently found that the worms of the greater wax moth can break down polyethylene, which accounts for 40% of plastics. The team left 100 wax worms on a commercial polyethylene shopping bag for 12 hours, and the worms consumed and broke down about 92 milligrams, or almost 3% of it. To confirm that the worms' chewing alone was not responsible for the polyethylene breakdown, the researchers made some worms into paste(糊状物) and applied it to plastic films. 14 hours later the films had lost 13% of their mass--apparently broken down by enzymes(酶)from the worms' stomachs. Their findings were published in Current Biology in 2017.

    Federica Bertocchini, co-author of the study, says the worms' ability to break down their everyday  food-beeswax--also allows them to break down plastic "Wax is a complex mixture, but the basic bond in polyethylene, the carbon-carbon bond, is there as well, "she explains. "The wax worm evolved a method or system to break this bond. "

    Jennifer Debruyn, a microbiologist at the University of Tennessee, who was not involved in the study, says it is not surprising that such worms can break down polyethylene. But compared with previous studies, she finds the speed of breaking down in this one exciting. The next step, DeBruyn says, will be to identify the cause of the breakdown. Is it an enzyme produced by the worm itself or by its gut microbes(肠道微生物)?

    Bertocchini agrees and hopes her team’s findings might one day help employ the enzyme to break down plastics in landfills. But she expects using the chemical in some kind of industrial process-not simply "millions of worms thrown on top of the plastic.”