Dec 21st 2018
On December 19th Gatwick airport, Britain’s second-biggest, was forced to close due to several sightings of drones（无人机）flying near its runways. The airport only reopened on the morning of December 21st. ① .
The potential for an incident of this scale has been recognized for some years now. The falling price of small drones in recent years has resulted in the number flying dangerously near aircraft to rise sharply. ② .
This is a threat that the authorities have to take seriously. Recent research suggests that small unmanned aerial vehicles (UAVs) can be much more damaging than birds — a surprisingly common cause of aircraft crashes — at the same impact speed, even if they are a similar weight. The researchers found that the drones’ rigid and dense materials—such as metal, plastic and lithium batteries—can put aero planes at much greater risk than a bird carcass（动物尸体）. If a drone were to hit an aircraft’s fan blades when it is operating at its highest speed, the blades could break and power to the engine could be lost.
③ . But it also underlined the potential for destruction that drones afford. The British police do not think that terrorism was the motivation behind the latest incident at Gatwick. According to the Daily Telegraph, a British newspaper, environmental activists are suspected of being behind the attack, which has happened before.
As attention turns to what can be done to prevent a repeat, two solutions stand out. The first is regulation. Regulators in America and Britain already ban drones from flying too close to airports. America has introduced a compulsory registration scheme for drones and Britain plans to follow suit.
But as the chaos at Gatwick shows, even serious punishments will not stop those intending to cause harm deliberately. ④ . Technology is the second, and more important, answer to the threat. In the US the FAA has experimented with a system. Drones can have pre-programmed software that keeps them away from prohibited areas, an approach known as “geofencing”. British engineers have come up with a system that catches drones with a net and then softly lands them with a parachute. Dutch police have even attempted to train eagles to catch drones in the sky and return them to their trainers as if they were song birds. The closure at Gatwick will give ideas such as these a mighty push forward.
1.Compared to birds, drones have become a more serious threat to airplane crash in that _____.
A.drones are much heavier than birds in general
B.drones usually fly even faster than birds
C.drones will attack airplanes on purpose
D.drones are made of rigid and dense materials
2.The sentence “The extended closure of Gatwick was a justified response to this threat.” should be put in _____.
A.① B.②
C.③ D.④
3.It can be inferred from the article that _____.
A.The decreasing size of drones recently has led to frequent accidents of this kind.
B.Among the solutions, technology is considered to be a more reliable one.
C.The FAA has adopted a “geofencing” system with the help of trained eagles.
D.The British police think environmentalists conducted the latest incident at Gatwick.
4.What can be a suitable title for the article?
A.Drones or birds, which is more harmful?
B.How to stop unmanned aerial vehicles?
C.Several drones close Gatwick airport.
D.Drones have become a pressing issue.
The brain has a powerful ability to remember and connect events separated in time. And now, in that new study in mice published in Neuron, scientists at Columbia’s Zuckerman Institute have cast light on how the brain can form lasting links.
The hippocampus—a small, seahorse-shaped region buried deep in the brain—is an important headquarters for learning and memory. Previous experiments in mice showed that disruption (中断) to the hippocampus leaves the animals with trouble learning to associate two events separated by tens of seconds.
“The traditional view has been that cells in the hippocampus keep up a level of continuous activity to associate such events,” said Dr. Ahmed, co-first author of the study. “Turning these cells off would thus disrupt learning.”
To test this view, the researchers imaged parts of the hippocampus of mice as the animals were exposed to two different stimuli (刺激物): a neutral (神经的) sound followed by a small but unpleasant puff of air. A fifteen-second delay separated the two events. The scientists repeated this experiment across several trials. Over time, the mice learned to associate the sound with the soon-to-follow puff of air. Using advanced microscopy, they recorded the activity of thousands of neurons (神经元) , a type of brain cell, in the animals’ hippocampus over the course of each trial for many days.
“We expected to see continuous neural activity that lasted during the fifteen-second gap, an indication of the hippocampus at work linking the auditory sound and the air puff,” said computational neuroscientist Stefano Fusi, PhD. “But when we began to analyze the data, we saw no such activity.” Instead, the neural activity recorded during the fifteen-second time gap was sparse (稀少的). Only a small number of neurons worked, and they did so seemingly at random.
To understand activity, they had to shift the way they analyzed data and use tools designed to make sense of random processes. Finally, the researchers discovered a complex pattern in the randomness: a style of mental computing that seems to be a remarkably efficient way that neurons store information.
“We were happy to see that the brain doesn’t maintain ongoing activity over all these seconds because that’s not the most efficient way to store information,” said Dr. Ahmed. “The brain seems to have a more efficient way to build this bridge.”
In addition to helping to map the circuitry involved in associative learning, these findings also provide a starting point to more deeply explore disorders, such as panic and post-traumatic stress disorder.
1.What can we learn about the hippocampus?
A.It weakens with the memory decline.
B.It is a brain region crucial for memory.
C.It serves as a tool of learning languages.
D.It is involved in the visual area of the brain.
2.The new study in mice indicates that ______.
A.continuous activity happens as expected
B.no neurons stay active at intervals of 15 seconds
C.a complex pattern helps the brain learn associations
D.neuronal information is stored in well-designed tools
3.From the last two paragraphs, we can infer that the findings ______.
A.inspire deeper explorations of disorders
B.provide evidence for language learning
C.build a bridge between different parts of the brain
D.help map some aspects of a person’s experiences
Keep the Summer Fun Going
Grand Ole Opry Package
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Hersheypark Vacation Package
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1.If you are planning an exciting wild jungle adventure, which vacation package will you book?
A.Grand Ole Opry Package.
B.Hersheypark Vacation Package.
C.Branson's Fun for Kids Vacation.
D.SeaWorld San Antonio Vacation Package.
2.Hersheypark Vacation Package is attractive in that it includes ______.
A.free accommodation
B.various milk chocolates
C.thrilling roller coaster rides
D.amusing animal performances
From poverty to a rocket scientist to the CEO of the Girl Scouts (女童子军), Sylvia Acevedo’s story is inspiring.
Sylvia Acevedo grew up on a dirt road in New Mexico. Her family was _______, living paycheck to paycheck. After an infectious disease _______in Las Cruces nearly killed her younger sister, her mother moved the family to a different _______. At her new school, a classmate _______her to become a Brownie Girl Scout. And from that moment, her life _______a new path.
The Girl Scout cookie program equips girls with basic _______knowledge. Women constantly in the sector said they got their _______through it. Sylvia Acevedo was there going door-to-door _______ cookies to all her neighbors. There’s a famous sales _______ that her troop leader gave her: you never leave the side of a sale ________ you’ve heard “no” three times, and to this day she ________ by that.
The Girl Scout experience in a way got girls ________. When they are earning different badges (徽章) , they have all those job skills that are ________related to what they’ve learned. On one camping trip, Acevedo’s troop leader saw her looking up at the ________—she didn’t know that there were planets. Her troop leader ________the Big Dipper, the Little Dipper and a few planets. Later, when the girls were ________ badges, Acevedo’s leader remembered her ________with the stars and suggested she try for her science badge. She went on to get a master’s in ________ from Stanford University, then became a rocket scientist with NASA, and then, in 2016, was appointed to ________ the Girl Scouts.
What the Girl Scouts taught her was determination and resilience (适应力) and she has kept that ________in her life ever since.
1.A.large B.happy C.poor D.close
2.A.control B.outbreak C.symptom D.victim
3.A.project B.neighbourhood C.schoolyard D.division
4.A.convinced B.advised C.forced D.allowed
5.A.took up B.took in C.took off D.took on
6.A.political B.cultural C.financial D.religious
7.A.start B.way C.head D.vote
8.A.allocating B.selling C.making D.tasting
9.A.campaign B.figure C.program D.technique
10.A.after B.while C.until D.since
11.A.lives B.gets C.passes D.judges
12.A.adopted B.hired C.noticed D.supported
13.A.gradually B.hopefully C.closely D.loosely
14.A.trees B.birds C.stars D.tents
15.A.pointed out B.ruled out C.sorted out D.brought out
16.A.wearing B.donating C.counting D.earning
17.A.satisfaction B.association C.combination D.fascination
18.A.engineering B.marketing C.teaching D.nursing
19.A.back B.head C.fund D.check
20.A.dream B.promise C.lesson D.standard
Lisa complained it was _______, having to go upstairs to make the coffee every time.
A.as clear as day B.a shot in the dark C.a pain in the neck D.as easy as pie
As a matter of fact, all people, ______they are young or old, are required to be citizens of high ideals, strict discipline, good education and communist morality.
A.no matter B.however C.whatever D.whether
