1 . Many of us think of sharks as powerful, mysterious, and lonely as they move through the deep. And nowonder the fish have long been portrayed in popular media as lone predators, appearing out of nowhere to attack. But that image has come under inspection in recent years, as shark researchers around the world have discovered the fish gathering in large numbers and interacting with others of their own species in ways that are obviously friendly.
Yannis Papastamatiou, a marine scientist at Florida International University, and his team used acoustic transmitters to record the interactions over four years of about 40 reef sharks around Hawaii. Their study found that reef sharks return to the same communities year after year, forming clear preferences for sharks with some friendships that endured throughout the study. In his 2016 study, he found that individual sharks tagged with recording devices had thousands of interactions with their peers, with some pairs spending up to four straight days together. The study also found certain sharks were unmistakably companions. “These weren’t random associations,” he says.
Finding out why sharks socialize — and how much of their behavior is cooperative — is a challenge, but there are some clues, such as food availability and warmer waters. Great white sharks, are showing up in record numbers along southern California beaches as the population has doubled since 1994. While great white sharks typically maintain distances of about 30 feet from each other and don’t seem too close, they are clearly drawn together by a preference for the area. In some cases, there may not be an obvious purpose for shark’s friendship. At the Bimini Shark Lab, Smukall and his colleagues found that young lemon sharks sought out companionship of other sharks for no clear reason. There’s growing evidence that lemon sharks have their own personalities, which may influence whether they spend time with other sharks, he adds.
More would be known about the intimate lives of sharks if the field weren’t so new, due in part to a lack of funding and sharks’ negative reputation. “We’ve only had about 20 years to really start studying sharks,” says Smukall.
1. Why do the reef sharks return to the same groups every year?| A．To move to other places together. | B．To find a better place to lay eggs. |
| C．To change the food chain of the sea. | D．To search for the company of other fish. |
| A．Global Warming. | B．Preference for an area. |
| C．Sharks’ personalities. | D．Food availability. |
| A．Sharks usually spend four days with their peers. |
| B．The relationship between some sharks is steady. |
| C．All the sharks were attached to recording devices. |
| D．Sharks have thousands of interactions every day. |
| A．Sharks always have a bad reputation. |
| B．Scientist will begin studying sharks in 20 years. |
| C．There will be a long way to go before knowing sharks completely. |
| D．It is unnecessary to put money into the research of the sharks. |
2 . There are 156 known species of glass frogs living throughout the neotropics. Recent advancements in genetics are giving researchers a revealing look into the lives of these one-inch-long tree dwellers, some of which are the size of a paper clip.
Scientists have discovered, for example, that male glass frogs in some species are stellar parents — a rare trait among vertebrates (脊椎动物). Males of at least 24 species not only protect their eggs from predators but also actively care for them. While the embryos (胚胎) develop, males of some species, such as the sun glass frog sit atop their egg clutch "like a chicken," keeping the eggs hydrated until they hatch into tadpoles (蝌蚪).
New research is also discovering how the glass frog's transparent belly forms. It's suspected that young glass frogs physically rearrange the insides of their cells and tissues to become transparent adults. Fluid between the tissue cells may also contain a substance that allows light to travel through.
Another mechanism that may allow glass frogs to blend into the green leaves on which they doze during the day is called "a biological mirror", a kind of shield or covering of crystals in many of their tissues, which reflects up to 30 percent of the light that normally reaches them. Those crystals amplify the light signal, and the frog's green looks brighter.
Many scientists studying glass frogs arc motivated by the fact that some of their subjects are disappearing—and fast. Agriculture, cattle grazing, and mining projects in the Andes are taking over the frogs' already fractured forest homes.
"As soon as they are discovered, many species are declared endangered," Guayasamin, a biologist in Ecuador, says "yet there could be an advantage in conserving such isolated ponulanons." All could be inspired to work together to set aside frog-rich patches of land as reserves, ensuring that these delicate creatures have a solid chance at survival.
1. What can we know about glass frogs?| A．They are regarded dangerous. | B．They are small animals. |
| C．They are of different colors. | D．They live in the water. |
| A．Strange. | B．Ambitious. |
| C．Excellent. | D．Different. |
| A．They physically change their cells. | B．They contain transparent fluid. |
| C．Crystals in their tissues reflect light. | D．Light signal makes them greener. |
| A．Stopping cattle grazing. | B．Building frog reserves. |
| C．Improving frog popularity. | D．Planting more forest trees. |
Venice is an attractive city between the sea and the sky. The city
Venice has a lot of worldfamous tourist
Sadly, the Italian city has been regularly flooded by rising sea water over the years. From November to February, sea level rises up to one and a half meters,
4 . My work started in 2003 at my local animal shelter’s Adoption Department. It seems like such a long time ago. In the 13 years that have passed, more than 50,000 animals have passed the doors of the shelter. Most of them, I do not remember. But occasionally there are animals who stand out. Tabby was one such animal.
Tabby was one of the many homeless dogs. What’s more, she was blind and deaf. Tabby’s chances at adoption seemed remote at best. But one day a woman named Loretta came to the shelter. Her son, Gary, who suffered from epilepsy (癫痫) had seen Tabby’s picture on the shelter’s website. They were interested in meeting her! Most boys would want a puppy, a dog who could grow with him and run through grassy fields on summer days. Tabby would never be able to do that. But as they say, "love is blind". After meeting her, they decided to adopt Tabby!
If Tabby’s story had simply ended with her successful adoption, it would still have been something very special indeed but it was what happened after her adoption that some might label as "magical" or perhaps even miraculous. As Gary and Tabby did everything together, they became so "in tune" with one another that Tabby began to telegraph Gary’s seizures (疾病发作) before they occurred, giving his family a warning that one was about to strike. What’s more, Gary seemed to be having fewer and fewer seizures since Tabby’s arrival.
How could it be? There are some things that happen in this world that challenge all logic and understanding. Sometimes, the best that we can do is to accept a miraculous thing, which we didn’t attempt to explain. Because when you try to explain it, you lose the beauty and wonder of it all.
1. Which sentence can be used to describe Tabby?| A．She was so lovely that she could be easily adopted. |
| B．She suffered a lot from the disease-epilepsy. |
| C．She was so strong that she could run very fast. |
| D．She was homeless and couldn’t see or hear. |
| A．Amazing. | B．Typical. | C．Interesting. | D．Special. |
| A．Gary learnt about Tabby from a magazine. |
| B．Gary was cured in the company of Tabby. |
| C．Tabby could indicate a seizure before it struck. |
| D．Most boys would have the same decision as Gary. |
| A．Love is Blind: a Miraculous Dog | B．Give Me Food: My Dear Master |
| C．Love is Everywhere: a Poor Dog | D．Take Me Home: My Dear Boy |
5 . I’ve always found that hiking in nature makes me feel happier, and of course decreased stress may be a big part of the reason why. But, Gregory Bratman, of Stanford University, has found evidence that nature may impact our mood (心情) in other ways, too.
In one 2015 study, Bratman and his colleagues chose 60 volunteers to take a 50-minute walk in either a natural setting or an urban setting. Before and after the walk, the volunteers were assessed on their emotional state and on cognitive (认知的) measures, such as how well they could perform tasks requiring short-term memory. Results showed that those who walked in nature experienced less anxiety and rumination (focused attention on unsatisfying side of oneself), as well as more positive emotions, in comparison to the urban walkers. They also improved their performance on the memory tasks.
In another study in 2017, he and his colleagues furthered these findings by focusing on how walking in nature affects rumination—which has been associated with the onset of anxiety—while also using fMRI technology to look at brain activity. Volunteers who took a 90-minute walk in either a natural setting or an urban setting had their brains scanned (扫描) before and after their walks and were surveyed on self-reported rumination levels.
Even so, volunteers who walked in a natural setting reported decreased rumination after the walk, and they showed increased activity in the subgenual prefrontal cortex, an area of the brain whose inactivity is related to depression and anxiety—a finding that suggests nature may have important impacts on mood.
Bratman believes results like these need to reach city planners and others whose decisions impact our natural spaces. “Ecosystem services are being included into decision making at all levels of public policy, land use planning, and urban design, and it’s very important to be sure to include findings from psychology into these decisions,” he says.
1. What did the 2015 study find about people walking in nature?| A．Their memory was improved. |
| B．Their mood remained the same. |
| C．They had more chance to succeed. |
| D．They preferred living in a natural setting. |
| A．Bratman’s theory. | B．The results of the 2017 study. |
| C．The process of the 2017 study. | D．The volunteers’ performance. |
| A．House designing. | B．City planning. |
| C．Physical training. | D．Health education. |
| A．Science Contributes to Better Health |
| B．Ways to Reduce Stress and Lift Mood |
| C．Studies Show Various Benefits of Hiking |
| D．Nature Makes You Happier and Less Anxious |
