相关试卷

Slow travel is about connecting deeply with your travels. Rather than rushing from one place to another, slow travelers treat each experience as an opportunity to learn and feel more deeply to the people, culture, and food they want to explore.  .

Relax and enjoy

Once, a vacation provided relaxation from the stress of everyday life. But over time, we began trying to put everything we want into a checklist. . Slow travel exchanges checklists for the chance to really enjoy a place. It's amazing how much more involved you can be when you're not in a rush. It's easier to relax and look forward to whatever the day brings.

Have more memorable experiences

. If so, the idea of slow travel may feel like you'll miss the latest Top

10. In fact, you free yourself from scratching the surface of everything without enjoying anything. Slow travel allows you the time to feel a destination and you will have more memorable experiences.

Meet people and actually get to know them

When you decide to take the slow travel route, you free yourself up to meet and spend time with others. You can meet locals at a park or restaurant and enjoy a conversation. Learn about the people on your food tour. You may even decide that you like someone enough to meet him/her later for lunch or a coffee. , because you are not rushing to the next big thing.

Traveling by plane, train, and bus has a bad effect on the environment. We can transport ourselves to one location and spend more time exploring it on foot, by bike or on horseback. That's less harmful to the planet than rushing to the next thing on the list with whatever vehicle that will get us there in a hurry.

A．Be more eco-friendly

B．Experience different means of transportation

C．This created more stress than we were escaping

D．Making a checklist makes your journey more organized

E．Here are some reasons we think you need to try slow travel

F．Your communication tends to be more relaxed and more real

G．Maybe you're used to jumping from one attraction after another

The giant panda's special black-and-white fur makes it one of the most recognizable animals on the planet. But why does it have this unique coloring? To hide from natural enemies, both in the snow and in the shadows, study lead author Tim Caro, a professor in the UC （University of California） Davis Department of Wildlife, Fish and Conservation Biology, said in a new statement. Moreover, the large black circles around a panda's eyes may help other pandas recognize it, the researchers said.

Understanding why the giant panda has such noticeable color has been a long-term problem to solve. To find out the answer, Caro and his colleagues looked at photos of pandas and 195 other carnivore （食肉动物） species, including 39 subspecies of bears. Then, they recorded the coloring on each area of those animals' bodies, and compared them with areas of the panda's body. "Compared with the previous studies, the breakthrough in this study was treating each part of the body as an independent area," Caro said.

The research team tried to figure out the purpose of the dark-colored furry areas. After going through many comparisons, the researchers determined that the white parts of the giant panda help it hide in the snow. In contrast, its black arms and legs help it hide in the shadows, they said. The panda's white-and-black coloring didn't appear to be related to temperature regulation. Nor did they find evidence that the dark circles around a panda's eyes helped to make them look cuter.

"This really was a great effort by our team, finding and scoring thousands of images and scoring more than 10 areas per picture from over 20 possible colors," study co-author Ted Stankowich, an assistant professor of bi ology at California State University, Long Beach, said in the statement. "Sometimes it takes hundreds of hours of hard work to answer the simplest question: Why is the panda black and white?"

Children at boarding school get the best night's sleep because of strict lights out time, according to a recent study, which was presented at Sleep Down Under, the 33rd yearly scientific meeting of the Australasian Sleep Association. Professor Kurt Lushington, a psychologist who led the study; said, "It is a naturalistic experiment showing the key to good sleep in teenagers is quite simple: a good timetable and no mobile devices（设备） at night."

Over the past 20 years, the time children spend sleeping has fallen and only half regularly get more than seven hours. The recommended amount is eight to ten. The biggest problems are smartphones and tablets （平板电脑） whose blue light wakes the brain, making it harder to drop off.

An Australian team compared sleep patterns of 15 to 18-year-olds at a school in Adelaide. The 59 boarders had to leave their phones in a kitchen area or on their desk before bed and turn their lights out by a set time. They slept for an average 8 hour 26 minutes a night compared with 7 hours 46 minutes for day pupils.

Lack of sleep affects mental health and school performance and causes behavioral problems. It has also been connected with the child obesity epidemic and other diseases. This year an American study found that teenagers who didn't get enough sleep took in extra sugar during a school year. They ate sweets, cakes, chocolate and biscuits and drank fizzy drinks to promote their energy levels.

Lushington recommends that parents reach agreement on not using a phone. This is most likely to work if they do likewise and offer other enjoyments, such as books. "I think if you put these rules in place, kids will go along with them," he told New Scientist.

I've lived in Cardigan Bay（卡迪根海湾） in West Wales since I was a few months old. You've got everything you need here. Hills, stunning beaches, nice coastal paths. As someone who loves the countryside, I've never wanted to leave.

I was lucky to find work I could do in this area. A lot of people do have to move away in order to find work. I started Adventure Beyond here about 30 years ago and we work all over the UK. We go up to Scotland, we work along the Thames. We've also taken groups to Canada, the Himalayas, places like that. But honestly, West Wales has got everything. We can do everything we need right here.

Cardigan Bay is pretty huge, but I find having grown up here there's a definite sense of belonging. There's an awareness that we're lucky to have these incredible sandy beaches, pebbly beaches, beautiful rivers, and hills. It's peaceful, and it's not overdeveloped. Of course, there are periods when it gets busy, but then the second schools go back and you pretty much get the beaches to yourself. There is a sense of community （群体） too, with a lot of good community-based clubs, such as the Poppit Sands Surf Lifesaving Club.

I set up Adventure Beyond to make my own work in the area. I love the outdoors, and I wanted to be in Cardigan Bay, so it was perfect. I've tried to always keep that personal touch. The clients（客户） will pretty much always meet myself and all the staff. We took a lot of people on through the Kickstart scheme（启动计划） and they've been employed with us for a few years. A lot of our clients have been with us since we started, too. There's a sense of family, which is quite special.

I won't mention a specific favorite place, but in general the beaches are just amazing. It's just a sort of wild west, really.

"Playing Shop" Social Activity

Children are invited to get behind the shop counter（柜台） of Susannah Place Museum, recreated 1915 shop.

This is a good time for your children to put on an apron（围裙） and become shopkeepers. They learn how to wrap（包裹） an egg, weigh out goods on a scale （秤） and count in pounds and shillings（先令）!

Suitable for the children between 5 and 7, the Playing Shop activity will see your children:

■ Use an old-fashioned shop scale.

■ Wrap goods.

■ Fill an order and make a delivery （配送）.

Tickets for Playing Shop are now on sale through sydneylivingmuseums.com.cn. Choose from the following periods:

9:15 A．m.-10:30 a. m. or 10:45 a. m.-12 p. m. on Wednesday, May 12, 2023.

9:30 A．m.-10:45 a. m. or 11:00 a. m.-12:15 p. m. on Friday, May 21, 2023.

Please note children must be accompanied （陪伴） by an adult.

You can continue your fun at Susannah Place Museum by joining a guided tour at 2 p. m., 3 p. m. and 4 p. m. at an additional （额外的） cost on the day.

When I was in middle school, my family moved to Seattle, where my parents started their new business — a small grocery store downstairs my house. As a girl of shy and reserved nature, I had to take a fresh start to fit into the sophisticated city life.

One sunny day, my school announced an exciting event, a talent show for the local food bank. Students were encouraged to showcase their unique talents in front of the public in the city hall on National Day. A buzz of excitement fed the school as everyone began preparing for the big day. Deep down, I felt a spark of curiosity and a desire to participate. However, my self-doubt held me back, "I don't have any special skills to share."

Days turned into weeks, and the talent show drew closer. I couldn't shake the upsetting feeling until one day, Emma, one of the most popular girls in my class, came to me while I was helping in the grocery store after class. "How about singing together in the talent show?" She grinned, "I heard you singing a tune, along the way back home. I can't help following you here." Gosh, I couldn't believe my ears. Emma, with personality and popularity, acknowledged my little talent. Since Emma had the world's prettiest voice, I felt like being favoured by fortune.

"You two? The talent show for the food bank?" My mum bent towards us and her face lit up. "A big occasion." Then a light bulb seemed to go in her head. "Why not practise right now upstairs? I bet you'll be a perfect match." Winking at us, she seemed to know we were thinking alike.

Emma and I embarked on rehearsing almost every single day after school. We brainstormed, exchanged ideas and rehearsed the scene. As the days rolled by, I was feeling pretty good about our act. But the day before the performance, Emma called that she had an acute stomachache and was not in any shape to perform.

注意：

1.所续写短文的词数应为150左右；

2.请按如下格式在答题卡的相应位置作答。

Paragraph 1: 

I was completely knocked out by the news.

Paragraph 2: 

Finally came the big moment.

1.对这一异议作出解释；

2.提出你自己的看法。

注意： 

1. 写作词数应为80左右； 

2. 邮件的开头语和结束语已给出，不计入总词数； 

3. 请按如下格式在答题卡的相应位置作答。

Dear Allen, 

In your e-mail, you expressed disagreement about our teachers speaking both English and Chinese in English classes.

Yours sincerely, 

Li Hua

Wandering sounds, irregular rhythms and a carrier of gentle emotions. This is the musical language of guqin, a plucked seven string instrument created in ancient China.

The earliest piece of guqin in China, (unearth) in Hubei province in 2016, dates back to the Zhou Dynasty. The body of a guqin is made of lacquered wood and the strings of twisted silk. its seemingly simple appearance, making a guqin is extremely demanding.  outstanding piece can take anywhere from two to several decades to craft. It is a crystallization of art and time.

The guqin was favored by the literati in ancient China. The most renowned guqin (music) was Yu Boya in the Spring and Autumn and Warring States periods.  he played his guqin in the mountains, a woodcutter named Zhong Ziqi heard the music and understood exactly  Yu wanted to express.

This deep understanding formed a strong bond between them, they became close friends. This is the famous tale behind the guqin masterpiece, Flowing Water, High Mountains. The piece (pass) down through generations and is considered one of the most famous and important (compose) in Chinese guqin music. This graceful dialogue, (flow) from brushed fingertips and travelling for thousands of years, is continuing to this day.

Andrew Powell was pulling envelopes from the large mailbox outside his contemporary house when he noticed something 1 : A tiny doll couple were sitting on a love seat inside the mailbox. A small note was attached. 

"We've decided to live here," the 2 read. It was signed from Mary and Shelley. Andrew initially figured that somebody must have left them there 3 . So he asked the neighbors whether anybody had left 4 in his mailbox, and everyone said no. Soon, Andrew and his wife discovered that the small couple had 5 a tea table, a pretty carpet and a pillow.

Over the next few months, additional items mysteriously 6 : a bed, a painting and a wood-burning stove, to name a few. For Christmas 2022, a decorated tree was left with tiny presents. But the gifts were taken back right after Christmas 7  Andrew could open the boxes to see if anything was inside. 

More than a year later, Mary and Shelley are still living rent-free in the mailbox, to the delight of the neighbors who now 8 Andrew's updates on the village's website to check the 9 . Andrew first posted about the tiny dolls on Aug. 21, 2022, hoping his fellow villagers might help solve the 10 .

"It's just somebody out there who is having some fun, giving us all a little community 11 . But whoever is doing this is obviously very 12 and clever," says Andrew's next-door neighbor.

Andrew says he now doesn't want to know who is 13 for the mail-box affair because he's hoping it will continue. "Also, people in the neighborhood are 14 it and some ask if I've thought about installing an outdoor 15 , but personally, I like the mystery of it."

Do you think you need to shout at yourself to force yourself to finish your homework? If so, think again. Research shows that practicing self-compassion (自我关怀) improves our mental and physical well-being and supports long-term success.

Self-compassion is the practice of being kind and supportive to ourselves. The opposite is being self-critical and mean to ourselves when we make a mistake.  These negative responses are related to depression, stress and reduced quality of life.

A 2017 study found people who practice self-compassion tend to handle stress better. Their bodies have less of a stress response when, for example, they meet with difficulties at work or school. Let's say they do poorly on a geometry test. Self-compassion helps them use the experience to make changes going forward, like seeking out a math tutor.

We can start with mindfulness. First of all, practice observing our thoughts — are they understanding or critical? Don't judge ourselves too severely then. Rather than getting caught up in how we could have done better, forgive ourselves and think about what to change while remaining respectful, and loving to ourselves. We can read a novel, play a musical instrument or kick around a soccer ball with friends.

With practice, we can learn to treat ourselves with kindness and unconditional love — not tough love.

A．So how do we develop self-compassion?

B．It may be more effective to be kind to yourself.

C．It includes letting go of your strict self-criticism.

D．Mindfulness is the key to practicing self-compassion.

E．But this approach does not make us feel or perform better.

F．They have more confidence to look for areas where they can improve.

G．Also, show ourselves kindness in ways that nourish (滋养) our spirit and body.

The only science fiction that ever really caught my attention when I was growing up, besides Star Trek and Robert Heinlein's Stranger in a Strange Land, was the novel Contact by Carl Sagan. When I was 15, I saw the 1997 film version of this. Later, as a 17-year-old adapting to my first semester (学期) at university, I read the book. Contact eventually became the gateway for me to try more popular science books.

One thing that interested me was the bitter fights the researchers got into with one another about their different ways of measuring the expansion rate of spacetime. On second thoughts, maybe this was a lesson I was supposed to draw from Contact, but, at the time, I didn't regard such politics as a scientist problem. Instead, what caught my attention was the portrayal of Eleanor "Ellie" Arroway, a scientist who searched for alien intelligence. In the film version, Ellie is seen listening to space using a pair of headphones connected to the Very Large Array (VLA)—a real facility in New Mexico.

Astronomers don't really do this for the purposes of actual research because there is rarely any point. This is the kind of detail that is unimportant for the film of Contact, but how it portrays radio astronomy is one of the inaccuracies I occasionally hear scientists complain about. I was lucky enough to observe the behaviour of some water molecules (分子) in the Orion nebula (猎户座星云) using the VLA for my thirdyear lab course. We didn't listen to the data. Instead, we processed it so that we could look at it.

That was probably the only time I ever excelled in the lab, and I was so excited to be a real­life Ellie Arroway. Later, I was forced to think more about the human aspects of my working experience. I witnessed unnecessarily heated arguments between scientists, complete with shouting and chalkboard punching (用拳猛击). But, thankfully, Contact had not only introduced me to the idea of radio astronomy as a possible career path, it had also given me a road map for remaining calm in the confused conflict of astronomical wonder and human politics.

While they can't pick out precise numbers, animals can comprehend that more is, well, more. From birds to bees and wolves to frogs, animals use numbers to hunt, find a mate, return to their home, and more. Researchers believe that this ability, known as numerical competence, plays an important role in how animals make these decisions. Andreas Nieder, a biologist at the University of Tübingen, explores the current literature on how different animals comprehend numbers.

Honeybees, for instance, can remember the number of landmarks they pass when searching for food in order to find their way back home. This ability can also be seen in animals choosing a larger amount of food over a smaller amount or in animals forming hunting groups. Wolves are more likely to hunt successfully if they have the right number of wolves in their pack for their prey (猎物) with prey like elk (驼鹿), only around six to eight wolves are needed, while hunting wild pigs requires a pack of nine to thirteen. Their prey also uses this concept to protect themselves—elk tend to live in small groups, which rarely have encounters with wolves, or gather in large groups to reduce the chance of any individual becoming prey. "They are assessing the number of individuals in their groups for their everyday life situations," Nieder says.

Furthermore, numerical competence also plays a role in attracting a mate. For example, male frogs sing "advertisement" calls to attract females. The females, listening to their complicated calls, choose the males that sing the most "chucks" in their calls.

Now researchers do have some sense of the rules that govern numerical competence in animals. For example, they count approximately (大概) rather than specifically and two numbers need to be more different for them to tell them apart as those numbers get bigger. However, Nieder argues that more research needs to be done. "I hope I can encourage behavioral ecologists to specifically explore numerical competence in the wild, and, in doing so, also open new research fields," he says.

Los Angeles residents Joe Blackstone and Jamie Mohn have long recognized the lasting impact storytelling can have on a child's life. Shortly after getting married, the couple began volunteering to read books to elementary school kids. Then, when they became parents themselves, they created the J3 Foundation to help organizations devoted to children's growth. But after learning two-thirds of fourth graders who cannot read effectively end up on welfare, Blackstone and Mohn decided to take a more hands-on approach: in 2018, they launched J3's Cozy Reading Club.

Each session of the two-hour, after-school program is free and includes outdoor activities and a healthy snack. Then, it's time for some comfortable reading. After teachers read a book aloud and the group talks about the storyline freely, the kids find a spot to sit while grabbing a book of their choice to look through. In the end, they get to choose two books to borrow and take home.

In its first year, J3's Cozy Reading Club served 15 students in one L. A．-area classroom. As of 2022, it had expanded to 17 schools across four different districts, impacting a total of at least 400 students, the vast majority of whom live in underserved communities. With impressive statistics backing it up 90% of the students have significantly improved their reading scores, and 95% say they've started reading for fun since taking part in the program——its founders have much to celebrate.

"Having more than 5,000 culturally relevant books available to them is so exciting. I love it when our students can see themselves and their classmates' lives reflected in the books they are reading. The hope of changing one kid at a time makes all the work worthwhile," Blackstone said.

Currently, J3 is in the process of raising $864,000, so the Cozy Reading Club can expand to an additional 24 Los Angeles schools and double its book collection to 10,

000. This is worthwhile. The National Assessment of Education Progress (NAEP) reported that 68% of U. S. fourth graders weren't skilled at reading in 2022, up from 66% in

2019.

Camp Kinneret

Located in the rolling hills of Agoura, California, Camp Kinneret provides children aged 4-14 with a classic, outdoor day camp experience. Working at camp is an opportunity to be part of an intentional, growth-oriented community as a role model and leader of your campers. Most staff will ride the bus to camp each day with their campers from various Conejo and San Fernando Valley cities. Summer camp jobs include:

• Day Camp Staff assigned to a specific group for the duration of the summer participating in all activities throughout the day. 

• Swim Instructors working in a team of 4-6 to ensure the safety of campers of all ages and abilities at the pool. 

• Activity Instructors leading campers at activity areas that include horse riding, animal care, nature ecology, wilderness play, farming & gardening, performing arts and more!

• Resident Camp Staff spending each week guiding kids through a variety of on-site and off-site adventure-based activities including backpacking, mountain biking, climbing and more!

Camp Kinneret allows you to gain a summer's worth of leadership development that you won't find elsewhere! Salaries are based on position and previous experience. The range for a first-year staff member is $5, 100-$7, 000 for a 10-week summer. Applicants must be college-aged or older, have summer housing available in the Greater Los Angeles Area and be able to make a commitment from Jun. 6th to Aug. 6th, 2022 (Mon. -Fri. , 8:30 am-4:30 pm).

If you are passionate about personal growth and development (for yourself and for others), fill out the online application and select a group interview to attend virtually or in person.

All I did was show my little sister how to grow plants. Dig a hole. Put in a seed. Cover it with dirt. Water it. Wait. " See, Laynie,"  I explained, " a whole plant will grow from this tiny seed. All we have to do is water it. " 

Laynie had her own watering can so she could " help"  me in the garden. One day, after everything was watered, she said, " We forgot something, Brad. "  She ran to the fence and started sprinkling water on another spot. I walked over and saw a fresh patch of dirt near the fence. 

" Did you plant something there?"  I asked. 

" Yes,"  she said. " I' m growing a pencil. " 

She stopped sprinkling. " My purple pencil got too small, so I planted it, the way you said. "

" But, Laynie—" 

" How long does it take to grow a new pencil?" 

I should have explained things right then, but I just muttered, " Uh. . . I never grew one before. " 

Later I got what seemed like a great idea. I dug up Laynie' s pencil and " planted"  a brand-new purple pencil. I fixed it with the erase r sticking up. 

Laynie was really excited when she saw it. " My pencil grew!"  she shouted. She drew pictures with it all afternoon. 

A few days later, Laynie was watering the same spot. " How long does it take to grow crayons?"  she asked. " I can' t wait!"  she squealed, giggling. . . She squatted down and whispered, " Grow. Come on, grow. " 

Two days later, new crayons sprouted their point y little heads, thanks to me. Laynie jumped up and down and yelled, " They look like flowers!"  She " picked"  them and ran into the house. Grandma thought Laynie was cute when she claimed that she had grown these things. I just kept my mouth shut! Actually, it was fun trying to think of what should grow from Laynie' s " seeds. "  And it was cool to see her get excited. 

One day I saw her patting down some dirt, so I knew she' d just planted something. " What is it this time?"  I asked. 

" It' s Molly. "  I gasped. Molly was Laynie' s goldfish! " She jumped out of her bowl again,"  Laynie said. " Grandma said we didn' t find her in time. "  Then Laynie picked up her little watering can and started sprinkling that spot. My heart dropped to my feet when she asked, " How long does it take to grow a goldfish, Brad?"  She knelt down to whisper " Grow, Molly. Grow!"  before she skipped back to the house. 

注意：1. 续写词数应为150个左右;2. 请按如下格式在答题卡的相应位置作答。

I sat down with my back to the fence and wondered what I should do then.

I hugged her tightly and suggested, " How about a funeral  for Molly?" 

网瘾 network addiction

注意：1. 写作词数应为80左右；2. 请在答题卡的相应位置作答。

Dear Jack,

Yours sincerely,

Li Hua

Acupuncture (针灸),  ancient Chinese medical practice, has been the treatment for countless patients for thousands of years. Up to now, this practice (become) a comprehensive and profound medical system. 

Acupuncture is an (amaze) treatment aiming to promote the body' s self-regulating functions. Its principles are in line with the ideas of traditional Chinese medicine,  emphasizes balance of bodily functions and overall well-being. 

Practices can vary in forms, including needle insertion, cupping and scraping. Needle insertion is carried  by inserting hair-thin needles into specific (point) on the body that channel energy (the qi). 

Acupuncture has been considered effective, particularly when (use) alongside with modern medicine.  its ancient Chinese origins, it is being used in 113 of WHO' s 120 member countries now, showing its widespread (recognize). 

As an ancient Chinese medical practice, acupuncture has earned (it) a great reputation across the world with magical effect. 

When I was growing up, I had an old neighbour named Dr Gibbs. He didn' t look like any doctor I' d ever known. He never 1  at us for playing in his yard. I remember him as someone who was a lot nicer than most of the adults in our community. 

When Dr Gibbs wasn' t saving lives, he was planting trees. His house sat on ten acres, and his life' s goal was to make it a 2 . 

The good doctor had some 3  theories concerning plant care and growth. He never watered his new trees, which flew in the face of conventional(传统的) wisdom. Once I asked why. He said that watering plants 4  them so that each following tree generation would grow 5 . So you have to make things 6  for them and weed out(淘汰) the weaker trees early on. 

He talked about how watering trees made for shallow roots, and how trees that weren' t watered had to grow deep roots 7  water. I took him to mean that deep roots were to be 8 . 

Dr Gibbs 9  a couple of years after I left home. Every now and again, I walked by his house and looked at the trees that I' d watched him plant some twenty-five years ago. They' re extremely tall, big since they have deep 10  now. However, the trees in my garden 11  in a cold wind although I had watered them for several years. 

It seemed that adversity benefited these trees in ways 12  never could. I stood there deep 13 . 

Every night before I go to bed, I check on my two sons. I stand over them and watch their little bodies, 14  of life within. I often pray for them. Mostly I pray that their lives will be easy. But I think it' s time to change my prayer because now I know my children are going to encounter 15 . 

An earthquake happens when two plates rub together. The earth plates travel in different directions and at different speeds.  In other words, earthquakes are the shaking of the earth' s surface caused by the earth' s rocky outer layer. The energy stored within is suddenly released. 

The damage an earthquake causes depends on where it is and when it is happening. If an unpopulated region is struck, there will be low loss of life or property.  Many of the areas at risk are largely populated now. Major earthquakes hitting those areas today could produce terrible damage. 

 Fortunately, however, most of them are unnoticed to the public because of the small Richter scale (震级). But large earthquakes such as the 1964 Alaskan quake that measured 9. 2 on the Richter scale, can cause millions of dollars in damage. 

 In 1972, a series of severe earthquakes struck Managua, Nicaragua. Fifteen years later, the city still looked the way it had a week after the earthquake hit, because the city was in such a mess that it didn' t have the money necessary to rebuild it. 

The shaking of the earth is sometimes not the greatest disaster.  In the 1906 earthquake, it was the fires caused after it that did the majority of the damage. An earthquake can also destroy dams high above a city or valleys, causing floods to sweep away everything in their path. 

A. Actually, there are several million small earthquakes every year. 

B. It is in the fires and floods that often the greatest damage occurs. 

C. Throughout history, there are numerous destructive big earthquakes. 

D. If it hits a large city, there may be many injuries and much destruction. 

E. So it is of great importance to predict the movements of the earth plates. 

F. If one plate is slowly forced under the other, pressure builds up until the plates break apart. 

G. The destructive damage of an earthquake can continue for years after the first shake. 

Each year, the discovery of new shark species underlines how little we know about ocean biodiversity. In a recent report conducted by Sibert and Rubin, they reported an unexpected finding: a large-scale extinction of sharks in the pelagic ocean, the largest ecosystem on Earth, about 19 million years ago. Their discovery suggests that some extinctions in the open sea of the past may have been mysterious. 

The study of Sibert and Rubin takes advantage of a system by using tiny, hard bits of shark skin and bony fish teeth that naturally fall from their bodies to the seafloor. These extremely small fossils provide a rich record of ancient oceanic sharks and their abundance for thousands of years. By studying fossils from many regions, the diversity patterns can give major insights into evolution (进化) of the open sea that would be otherwise unknown. 

Sibert and Rubin quantified(量化)a past extinction of sharks, reporting a 90% decline in number and >70% drop in diversity. They found that nearer-shore sharks appear to survive, but migratory ones go extinct. The finding of this study is that sharks had undergone a widespread extinction that reorganized their communities from 16 million to 20 million years ago. 

Sibert and Rubin narrowed the disappearance of sharks to a window of time under 100,000 years around 19 million years ago, but the causes of this event remain unclear. Because this time period does not stand out as a period of major climatic change, the authors do not attribute(归因于) environmental factors as an extinction driver. As for other causes, the loss of shark diversity is directly linked to overfishing. 

The loss of sharks from the oceans has profound, complex, and unavoidable ecological consequences because their presence reflects the stability of marine ecosystems. Yet, one-quarter of the global diversity of sharks is currently threatened with extinction. Despite recent improvements in conservation actions, shark communities never recovered from a mysterious extinction event 19 million years ago; the ecological fate of what remains is now in our hands.