题型:阅读理解 题类:模拟题 难易度:普通
湖南省湘潭市2019届高三下学期英语第二次模拟考试试卷
Hotshot jet pilots are no match for cliff swallows. The birds rocket over bridges and skim over lakes, rushing forward at accelerations that would knock an Air Force. By tracking these contests with high-speed cameras, a new study gives the first, in-depth peek into avian aerodynamics (鸟类空气力学) in the wild. "The findings may even provide insight into how to design better micro air vehicles-tiny drones. This technology will be brilliantly useful," says biomechanics expert Jim Usherwood of the United Kingdom's Royal Veterinary College in Hatfield. "High-resolution field studies like this have never been done before for birds."
For cliff swallows, the trouble starts when they return from wintering in South America to their summer homes in North America. After arrival, they seek out their old mud nests—usually located under concrete bridges and freeways-and start rebuilding their homes. But rather than hunt down a fresh supply of mud, some swallows prefer stealing supplies from their more hardworking neighbors. Others take things further and will even lay an egg or two in their neighbor's nest before taking off.
Battles in the air follow if the invaders are caught in the act, and a new study takes advantage of these fights to learn how birds perform high-speed maneuvers (演习). The team placed three cameras along a North Carolina lake crossed by a highway bridge that houses several cliff swallow nests and waited for the battles to commence.
The team was surprised to learn that most of the time, chasers copied the move of fleeing invaders. Swallows also pull very hard turns to escape an enemy, with one extreme case reaching 7.8 gravity. Fighter pilots usually pass out at about 5 or 6 gravity, which is why these experiments have earned interest, and partial funding, from the Office of Naval Research. The Navy may use the findings to build better guidance systems for micro air vehicles. However, the swallows' biomechanics are complex, and now the team is simply trying to collect a few tricks.
Destination Travels
78 Soho St,
New York, NY
Dear Ms Pierce,
Thank you for trusting Destination Travels for your honeymoon plans. This letter includes all the information regarding the flights and accommodation arrangements we have already agreed on.
Date | Flight No. | Place/Time Depart | Place/Time Arrive |
August 6 | UA 674 | New York, JFK 6:30 AM | Puerto Rico Int. Airport 9:00AM |
August 15 | UA 673 | Puerto Rico Int. Airport 1:00 PM | New York, JFK 3:30 PM |
On arriving at Puerto Rico Int, Airport, a representative of The Caribbean Hotels &Resorts will be waiting for you in order to transfer you to the hotel. The transfer to and from the airport is offered by the hotel as part of your honeymoon package. The reservation has been made for a nine-night stay under your future husband's last name. The price of the newlyweds' suite includes breakfast and one more meal at the hotel restaurant. You can also use all of the hotel facilities—pool, gym, sauna, etc. for free as part of your honeymoon package. In addition, you can take scuba diving or snorkeling classes with the hotels trained staff at a reduced price—40% off.
Thank you for choosing Destination Travels. We guarantee your honeymoon with us will be an unforgettable experience. To aid us in improving our service, please visit our website at www. destinationtravels.com and complete the questionnaire.
Destination Travels wish you all the best.
Sincerely.
Rebecca Simms
Customer Service Manager
Destination Travels
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