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A new study reveals that trees can communicate and warn each other of danger. "For the first time, researchers have been able to visualize plant-to-plant communication, "said Masatsugu, senior author of the study.

The idea of talking trees started to take root in the 1980s. Two scientists found that damaged trees began producing chemicals that made their leaves unappetizing and indigestible to discourage insects. The trees then sent chemical signals to one another through the air. Over the past four decades, scientists have observed this cell-to-cell communication in more than 30 plant species. 

Past research shows plants communicate with their surroundings by releasing chemicals known as volatile (易挥发的)organic compounds. One class of these compounds are released when a plant is injured: green leafy volatiles. These are released by, as the name suggests, pretty much every green plant with leaves, and are produced when a plant experiences physical damage. An example of these compounds is the smell released from fresh-cut grass. 

In the new study, Masatsugu and his colleagues manually damaged leaves and placed insects on tomato plants to trigger the release of various green leafy volatiles. After testing many of them, the team found it seemed to increase calcium ions(钙离子)inside cells. The calcium signaling is like a switch to turn on the defense responses from the plants. 

With this new understanding, researchers say plants could be immunized against threats and stressors before they even happen. For instance, exposing healthy plants to insect-ridden plants or the associated green leafy volatiles could boost their genetic defenses, so farmers use less pesticides. The revelation could also help make plants more resilient(有复原力的)during a drought, signaling the plants to conserve more water. 

Last year, there were 38 student members and a full-time teacher in the school band. But over the summer, the director took another job and the school board had no applicants for the vacant position. 

"It was such a downer, " remembers Jadyn Lane. "But we were given a choice--we could sign up for other electives(选修课)，or find a way to make the band work. " Most students signed up for other electives, but 10 students decided to stay.

"It wasn't an option to quit, " says Hailey Fitzgerald. "I've been in the band for seven years. I love it! It's too important for too many reasons. " The students elected Hailey as director, a position she accepted on the condition they would all work together and share responsibilities. They recruited Casey Griffith and Jennifer Nail-Cook to be their official faculty advisors. Casey did the paperwork, and Jennifer helped with the music.

They directed themselves. Front and center on the band room whiteboard are a set of rules which they created themselves. In addition, they made a calendar (日历) of their upooming events, like football games. It included a daily countdown to each event so they'd be prepared. 

Perhaps most importantly, they decided which instruments were necessary to make a band of this size work. Most of them were drummers. How could they play those instruments with the people they had? "Several members switched instruments and some even learnt brand new ones, " Hailey says.

The time came last month for their first public performance. It was a home football game against Richwood. They had no idea what to expect. Would it work? Would the crowd cheer them on? Would they cheer up the football team? To their surprise, a group of students made posters for the band and hung them at the entrance to the football field. "We thought some people didn't even know we still had a band, " says Jadyn. But their classmates had been paying attention and wanted to make their first game special. And their school won.

There are some new inventions in the field of artificial intelligence (AI). Let's have a look. 

Invention 1:A system to identify Parkinson's disease

The system works by measuring a person's breathing patterns during sleep. The researchers noted that early signs of Parkinson's disease are not easy to discover. But the team said the experiments showed that with just one night of sleep, the AI system can correctly identify Parkinson's disease up to 86% of the time. 

Invention 2: A tool to interpret pig emotions

The scientists developed an AI-driven algorithm to identify a series of emotions the pigs could be experiencing. The study centered on more than 7, 000 audio recordings of pigs in different situations. The researchers said the tool can lead to further systems farmers can use to improve the productivity and well-being of their animals. 

Invention 3: A system to identify and predict smells

The scientists built on past research to produce a brain-like technology model to create a"principal odor map" to identify molecules related to smells. The team said such a system can be used across many different fields, including the healthcare, food and fragrance industries, The researchers reported that the system can be used to help fight one of the world's biggest health problems--diseases spread through insects.

Invention 4: A tool to fill in missing words in ancient writings

The tool， called Ithaca, is designed to help historians repair the writings and identify when and where they were written. The team said that when historians worked on their own, the success rate for repairing damaged inscriptions was about 25%. But when humans teamed up with Ithaca to assist in their work, the success rate jumped to 72%. 

假定你是李华, 你校外教老师Mathew让以小组为单位做一个关于"Sports and Fitness"的项目, 请你作为小组长给老师发一封邮件沟通有关事宜。内容包括: 1. 项目内容以及进展;2. 寻求建议。

注意： 1. 写作词数应为100左右;2. 可以适当增加细节, 以使行文连贯。

Dear Mathew, 

Yours, 

Li Hua

假定英语课上老师要求同桌之间交换修改作文, 请你修改你同桌写的以下作文。文中共有10处语言错误, 每句中最多有两处。每处错误仅涉及一个单词的增加、删除或修改。

增加： 在缺词处加一个漏字符号(八), 并在其下面写出该加的词。

删除： 把多余的词用斜线(l)划掉。

修改： 在错的词下画一横线, 并在该词下面写出修改后的词。注意： 1. 每处错误及其修改均仅限一词;2. 只允许修改10处, 多者(从第11处起)不计分。

There are many unforgettable person around us. But for me a most unforgettable one is my English teacher，Mr. Liu. That frequently brings back my memories is his great qualities. First，he gave us the greatest gift a good teacher could offer-an awakening of a passion with learning. He led us to the beautiful of the English language. Furthermore, l attracted by his lively wisdom. We students were always eager to attended his class because his lectures were humorous delivered. Although it has been nearly five years since I attended his last class，but he is the talk of our classmates，and I know part of her has already stayed in my heart. 

As one of the three major drinks in the world，tea is also the most consumed drink after water on earth. Since tea trees  ( discover) thousands of years ago，the drink has become intimately integrated with daily life and has developed intounique culture. 

How could such a little leaf from nalture generate such great power?An ongoing exhibition( focus) on tea culture manages  ( explore) the answer by offering visitors a comprehensive view of the drink. 

The World of 'Tea: Special Exhibition of 'Tea Culture takes place at the Wu Men Exhibition Hallof the Palace Museum from September 2 to November 30 in Beijing. It displays 555 items( attach) to tea culture，many of are representative collections of 30 cultural institutions and museums at home and abroad. 

Further more，it also provides insights into a cultural phenomenon's origins, evolution and ( remark) achievements while emphasizing how it has acted as a unifying thread connecting diverse regions and fostering the integration of various ethnic groups. Using tea as a medium, it displays the essence of Chinese tea culture， and also embodies the Chinese philosophical( pursue) of unity between heaven and humanity. 

Wang Guangyao，director of the show and also a researcher at the Palace Museum，says，" We want our audience to ( complete) lose themselves in the show by settinginteraction spaces".

For many young Canadians，planting tlrees is more than just a job. It's a way of 1 —and itcould be catching on，thanks to a popular2  by Leslie. While working for a logging company, the 29-year-old filmed herself using the 3 method that allowed her to plant 4, 545 trees in asingle day. She said that the summer work is incredibly 4 . Many college students are 5 totree planting as a summer job，for which they receive 13-27 cents per tree. 

ln Canada，planting tree is not easy work ，according to Leslie. Not only is it6  tiring，butit also7  laborers to the bad weather. 

"lIt could start the day off8 and then minutes later， it will just be raining or snowing. Younever know what to9 , " she described. "There were some days that we were planting through aheat 10 , so we had like 37-to-40-degree weather for several days straight and that was really11 . "

Leslie has also had to 12  being bitten by mosquitoes while walking through rocky places. Then，there's the threat of local wildlife becoming 13 . While Leslie herself has only seen mostlarge animals from a distance, a 21-year-old woman performing the same14  just survived a bearattack last week. 

So far，Leslie has planted a total of 372, 290 trees in the past few years. 15 , she's stillnowhere near beating the Guinness World record. That honor 16 Kenny Chaplin，who onceplanted 15, 170 trees in 19 hours. After 35 years on the job，he says he'd 17 it to anyone. "I think every parent in Canada should be18 their kid out tree planting because it will takeyour child and it'll turn them into a worker, " he 19 . "They'll learn how to work, and they'll have20 . They'll have money in their pockets. "

Have you ever thought of yourself as the main character of a heroic adventure? lt could be good for your health. Research suggests that imagining yourself on a hero's journey could help you achieve amore meaningful life. You might be familiar with the hero's journey.  Mulan, and Harry Potter courageously facing their trials，all take this journey. How can you start imagining your life as a hero's journey? Here，experts share some strategies. 

Keep a journal. Ask yourself: What makes you you? Describe your personality and core values. Think about events in your life that made you who you are today. Then consider the challenges that stand in your way，and which friends can help you on your journey. 

Change the way you see obstacles. Going through a tough time? See your problems as challenges. A challenge is a chance to develop strength and be the hero of your own story. 

Go on more heroic adventures. "We like people who have new experiences and grow from their challenges. "Roger says. lt can be simple，like walking a new route to school. Or it can be dramatic，like borrowing a bike and riding it to school.

Say you're facing a big challenge. Thinking of a favorite hero's story can help you have that eagle-eye view of what might be next for you, or what you should be paying attention to. Storiesbecome this map that you can always turn to. That can be reassuring. It reminds you that a new chapter almost certainly awaits you. ·

A. So seek out something new. 

B. Writing down a few sentences can help. 

C. When you need a boost，think of your heroes. D. It's a common storyline in books and movies. 

E. Think of them as opportunities for growth and learning. 

F. They return home to benefit their community with what they've learned. C. The way people tell their life story shapes how meaningful their lives feel. 

In the roughly 250 years since the Industrial Revolution the world's population，like its wealth, has exploded. Before the end of this century，however，the number of people on the planet couldshrink(缩小) for the first time since the Black Death. The root cause is not an increase in deaths, but a sharp fall in births. Across much of the world the fertility rate， the average number of births per woman，is collapsing. Although the trend may be familiar，its extent and its consequences are not. Even as artificial intelligence( AI) leads to optimism in some quarters， the baby bust(婴儿荒) hangs over the future of the world economy. 

 The result is that in much of the world，the patter of tiny feet is being drowned out by the clatter    of walking sticks. The prime examples of ageing countries are no longer just Japan and Italy but also include Brazil，Mexico and Thailand. By 2030 more than half the inhabitants of East and South-EastAsia will be over 40. As the old die and are not fully replaced，populations are likely to shrink. Outside Africa，the world's population is forecast to peak in the 2050s and end the century smaller than it is today. Even in Africa，the birth rate is falling fast. 

Whatever some environmentalists say，a shrinking population creates problems. The world is not close to full and the economic difficulties resulting from fewer young people are many. The obvious one is that it is getting harder to support the world's pensioners(养老金). While the rich world currently has around three people between 20 and 64 years old for everyone over 65, by 2050 it will have less than two. The implications are higher taxes，later retirements，lower real returns for savers and, possibly，government budget crises. 

Eventually，therefore, the world will have to make do with fewer youngsters—and perhaps with a shrinking population. With that in mind，recent advances in AI could not have come at a better time. Al economy might find it easy to support a greater number of retired people. Eventually AI may be able to generate ideas by itself，reducing the need for human intelligence. Such innovations will certainly be in high demand. 

Back in 2019，three Chinese scientists were playfighting during a break from working in the Chongqing Province，China. One was kung-fu kicked into a rock , causing an opening in the rockface. Inside，a wonderful fossil(化石) lay undisturbed，preserved for millions of years. 

The fossil was a jawed fish，some 439 million years old，and the findings from the Chongqing site，along with other fossil findings in nearby Guizhou province，have excited the science world，as they are 11 million years older than any fish fossil found before. It is a significant discovery because scientists have suspected that jaws evolved(进化) some 450 million years ago, but there had yet tobe any fossils that supported this theory. The oldest fossils with jaws found were 439 million years old. 

In this discovery，though，there was a new species of shark that was 439 million years old，with a full jaw. 

"All these things are still like dreams, "said Zhu Min, who led the research teams that recently published four papers on the discoveries. "Today we are staring at complete early fishes，11 million years earlier than the previous oldest finds. These are both the most exciting as well as the most challenging fossils I have had the privilege to work on. "

Some of the fish that were discovered were placoderms，an extinct class of fish that have hard plates that formed a shield around the head and trunk，while others were an ancient type of shark. 

The scientists found the oldest-known teeth of any vertebrate(脊椎动物)，14 million years older than any previous findings，as well as two other shark descendants. China has been the site of numerous discoveries in recent years，including fossils of feathered dinosaurs，as well as the oldest known animals on Earth. 

"The discovery of the Chongqing site is indeed an unbelievable miracle of fossil hunting, "Zhuadded. "Suddenly we realized we have found a jaw-dropping fossil site. We are now close to the core of solving the fishy tree of early jawed vertebrates. "