1 . Why humans make and appreciate music is an evolutionary (进化的) mystery. Recently David Schruth and his colleagues have a new explanation. They say the roots of human music can date back to the branches of trees more than 50 million years ago, when the first primates (灵长类) appeared. Early primates moved around forest by leaping (跳跃) from branch to branch, a very dangerous way to travel that relies on hand and eye working together and control over muscles.

Schruth argues that a primate that calls in a musical way is advertising that it has fine control over its vocal (声音的) muscles. This might have convinced other primates that the caller also had fine control over its body. His another research shows the species that leap the most tend to have more complicated calls, which the team jokingly named as ‘protomusical’.

Hagen, a worldwide famous scientist in this field, commented on the research: “Some people would not include what we see in primates and songbirds as music. But I do see a continuity between human music and primate vocalizations”.

Hagen doesn’t think human music has a single, simple explanation. He argues that human ancestors originally used music-like vocalizations in two ways: groups vocalized together to send

All these ideas might be compatible, says Hagen. Protomusic could have evolved in primates both to attract companions and for territorial signaling. Later, as early humans began cooperating in large numbers, protomusic might have been repurposed so it could attract rather than frighten outsiders, while also strengthening social bonds within groups.

2 . That summer, I went to a small and rather remote village of Manitoba’s as a substitute for a sick teacher. It was a very poor village with a few humble wooden houses. There was nothing but the spruce around me. Could I leave a deep impression on the children in just a month? Is a month really worth the effort? I was really doubtful about these two questions.

Maybe the children had the same ideas, because I had never seen so depressing, sad, and even bitter facial expressions. I had little experience in teaching, and my age was like that of those children.

Most of them had thin eyes, dark skin, and shiny black hair, which indicated they were mixed blood children of French and Indian.

At nine o’ clock, the classroom was already as hot as a stove. I didn’t know where I should start. Then I called from a list of names, expecting the response. They stood up, and gave me the reply. However, when Yolanda was called, there was no response …Still no response …About 15 seconds later, a voice came from the back of the classroom with the buzzing of flies. “She’s dead. She died last night.”

The tone of the child’ s voice was astonishing but plain, and perhaps nothing could be more painful than to narrate in that tone. “Ah!” I cried out, not knowing what to say. The children and I looked at each other for a long time and we were silent. I understood that what I had seen from the children’s eyes and faces, which I had thought was the expression of indifference, turned out to be a great pain.

“Since Yolanda was your classmate, would you like to see her at four o’ clock after school?” There was a smile on the children’s serious little faces. It was a smile, though formal and sad.

After four o'clock, I saw that many children were waiting for me at the school gate. There were more than 20 children in total. Some of them walked in front to guide me. The others held me tightly, which almost made me unable to walk. Five or six younger children took my hand and gently led me forward, just like leading a blind guy. I unconsciously remembered those names, and they are still fresh in my memory, including Yolanda.

3 . Why are pandas covering themselves with horse droppings? Researchers in China spent a decade studying this question. It really is something that some mammals will do in the Qinling Mountains in China. The pandas nose out fresh horse droppings, lay themselves down and roll their bodies in the dung(粪便).

The behavior may help pandas tolerate cold temperatures because a compound in horsedung, the researchers propose in the paper published Monday in the Proceedings of the National Academy of Sciences, may help make pandas less sensitive to cold. “There are all kinds of reasons you want to stay away from dung.” Dr. Bowie said. She added that if they really are doing this, there must be “a clear fitness benefit”.

Field observations revealed that wild bears also seemed to smear themselves with horse droppings, preferentially engaging with dung during the cooler fall and winter months.

A chemical analysis of the dung revealed two compounds called sesquiterpenes(倍半萜烯), which are commonly found in plants. Further lab experiments showed the sesquiterpenes were gumming up(破坏)a type of cold-sensing protein for pandas and many other animals, including humans. “In theory, these chemicals, when applied topically like an ointment, might temporarily help pandas tolerate cold,” Dr. Wei, who was involved in the study said. “It's still unclear whether other animals might also cover themselves in dung for warmth.”

Isaac Chiu, a neuroscientist at Harvard University, praised the team's work, but added that the sesquiterpenes the researchers found in horsedung can do far more than weaken an animal’s ability to sense cold.

5 . "For years, we had seen a lot of old villages dying slowly before being torn down. It's such a shame. So I wanted to do something," says Zhang Lei, a professor from the School of Architecture and Urban Planning at Nanjing University.

Zhang's two design works for Librairie Avant-Garde, the Yunxi Library bookshop in Tonglu county's Daijiashan village and Chenjiapu Bookstore in Songyang county, both in East China's Zhejiang province, were opened respectively in 2015 and 2018. The villages have since seen increasing number of visitors. Hostels have been built and, as a result, property prices in the villages have soared. For instance, the annual rent of a house in Daijiashan village was 2,000 yuan ($306) in 2015, but has now grown to 8,000 yuan.

Similarly, Chenjiapu village used to be dying despite a history stretching back 600 years. The bookstore, however, means that holidays bring so many visitors that there are often traffic jams on the road leading to the village. "I never thought that a small bookstore could change the fate of a village," he says.

When Qian Xiaohua, founder of Librairie Avant-Garde headquartered in Nanjing, started opening bookstores in the countryside six years ago, he met with a lot of doubts and questions. After all, bookstores in cities, with much bigger populations, could barely survive due to online competition. Even more surprisingly, Qian prefers targeting old villages that are losing their young people, with just the elderly and children left behind. Those villages are usually located in picturesque surroundings, many with historical details. Qian, accompanied by architects, will then choose old buildings from the villages to be renovated into well-lit modern bookstores that remain true to their original structures and decorative aspects.

Since April 2014, Qian has opened five bookstores in the countryside. All have attracted large numbers of tourists and even young villagers to return home. Apart from their commercial success and subsequent economic revival of the villages, these bookstores have become new public spaces for locals, benefiting the development of rural areas in the long run.

7 . Arguster grew up on his family’s farm in a remote village. Planting cash crop — cotton, they were breaking even and had to make ends meet. In his childhood, there were nine kids at home. All the boys were in one room with two beds. Two slept at the head while two slept at the foot. Therefore, there was one thing about their feet — washing them before crowding onto the bed.

When there was a hole in Arguster’s jeans, his mother would put a patch on it. However, the hole kept going. It was the naughty kids, Arguster included, that took the jeans out, hung them on a line and shot them to put holes. Aware of that, however, Ben, the father, didn’t rebuke them, knowing it might be the only way to bring laughter to his kids.

Arguster’s first lesson in economics was taught by Ben. The childish kid had worked and made a little extra money. He couldn’t help admiring himself, “I make six dollars! Six dollars! Man! I’m on the top of the world!” With a great thrill, Arguster decided to go to fair, where he played games, ate cotton candy... When asked by Ben how much he had spent, with his head down, Arguster replied, “Daddy, I spent it all...” Looking at his messy hair, Ben sighed, “Boy, you spent all your money and haircut’s gone up to 75 cents. I’m afraid...” From then on, Arguster always kept enough money to get himself a haircut.

Ben taught his kids how to do the right thing and wanted them to do the right thing, which Ben tried to pass on to his kids, in his own way. Ben started a syrup mill(糖坊). People in the community brought their cane and millet for Ben to grind up (磨碎) for syrup. When people paid with buckets of syrup, Ben refused. Arguster got confused, “Daddy, why don’t you let these people pay you?”

“Because we got enough syrup to last for a long time! Son, these people don’t have money to pay. That’s the only way they can pay.”

10 . This year's hottest destination is Mars. On 23 July, China launched the Tianwen-1 mission to the Red Planet — one of three spacecrafts' planning to head there in 2020. This is China's second interplanetary mission, but the first that the nation has launched on its own. The other, Phobos-Grunt, was a cooperation with Russia that didn't make it out of Earth's orbit after blasting off in 2011.

The new mission, called Tianwen, translated as "questions to heaven" — consists of an orbiter, a lander and a rover, the last of which will be named via a public competition. "It's very ambitious because it's a four-part mission: there's the launch, getting into orbit, the landing and the rover, and every single step has to go right, says space consultant Laura Forczyk. All those steps must work on the first try, an achievement no other space program me has accomplished on a Mars mission because of the difficulty of landing there.

If all goes well, Tianwen-1 will arrive at Mars in February 2021 and the lander and rover will touch down two or three months later. They will take pictures from the surface, measure the soil composition, make radar observations of the planet's underground structure and observe Mars's magnetic field. Due to the harsh environment on Mars, the rover is expected to last about 90 Martian days. It weighs around 240 kilograms, about the same as China's Yutu-2 rover, which is currently roaming the moon. "The Chinese mission to the far side of the moon has been hugely successful, so they are building on that success now," says Forczyk.

The orbiter, which will relay data from the lander and rover back to scientists on Earth, also carries a suite of scientific instruments. It has two cameras and a spectrometer (光谱仪), which it will use to create a map of the mineral composition of Mars's surface, as well as radar and detectors to examine particles in the Martian atmosphere. It will also look for deposits of water ice that could be helpful for future explorers.

Tianwen-1 won't be alone in Mars orbit. The United Arab Emirates has just launched its first mission to Mars, and NASA's Perseverance rover is set to launch on 30 July. These missions are all leaving now because Mars is at its closest point to Earth, which happens once every two years.