I went to the Tsavo National Park in northern Kenya for a film. We set off early for a distant water hole. A huge elephant covered with dry mud, drank calmly and deeply. He might have traveled 50 km to reach the water. He wasn't going to hurry now. We thought he'd drink a while and rest in the shade, and then drink again. What actually happened was that he drank deeply and stepped away. Then he suddenly fell down. Within minutes he was dead.

    We called animal doctor Jeremiah Poghon immediately. He removed the head of a poisonous arrow (箭) from the elephant's body, and let out over 100 liters of drug—the result of the elephant's meeting with a poacher (偷猎者) months before.

    Today's poacher fires an arrow, covered with poison, into the body of an elephant. If the poacher is lucky, the elephant might die in an hour or two; if not, he might have to follow the elephant for days before it dies. Often the arrow head fails to kill the elephant at once—it doesn't mean the poison won't finally kill the elephant, but it will be a slow death.

    Living in Tsavo through these times, I could see the results of poaching from time to time. When I think about the death of that elephant, what stays with me is the great silence after the shocking sound of his body hitting the ground. I couldn't escape the feeling that with the death of such a large animal, the world seemed to be a poorer and emptier place.

    South Africa is a multiethnic society encompassing a wide variety of cultures, languages, and religions. It has 11 official languages. If you want to say hello, it's "sawubona" in Zulu, and "hallo" in Afrikaans. Now, South Africa's school children may start using "ni hao" to say hello.

    The country's education minister says, the nation is adding the Mandarin language teaching in some schools. Mandarin is the official spoken language of China. That country is a major trading power for South Africa.

    A recent agreement between the two nations centers on five areas of cooperation. They include development in basic education, school books and lessons, mathematics and science, teacher training and career education and research.

    South Africa officials have not said how much they teaching Mandarin will cost. Troy Martens is an officials with South Africa's Ministry of Basic Education. She says the new partnership is extremely valuable.

    A public opinion study last year found that South Africans have mixed feelings about China. The survey showed 46 percent of South Africans do not like the spread of Chinese ideas and customs in their country, the results also showed that 60 percent dislike Chinese music, movies and television.

    But Ms Martens said Chinese trade is more important than those feelings. She said it is extremely helpful to learners in South Africa to study Mandarin as well as Chinese culture. And she said not every school will offer Mandarin.

    “Now this will not be compulsory, it will not be for every school, and it will not be for every child. But for schools that feel they have the capacity to offer Mandarin as a subject, we think it is a great opportunity for South African learners to be exposed to this international type of language,” said Martens.

    Lisette Noonan heads the 80-year-old Pretoria Chinese School in South Africa's capital. The school serves about 500 students from kindergarten to grade 12. Every student studies Mandarin.

    Ms Noonan says the school welcomes the new cooperation between South Africa and China. She said it is in the best interests of children to study Mandarin. She said that especially true with China becoming what she called “a huge economic power in the world”

    There is a breakthrough in building aircrafts. Bendable wings covered with overlapping(部分重叠) pieces resembling fish sizes could be used to build swifter, fuel-efficient aircraft, a new study finds.

    Nowadays, conventional aircrafts typically rely on ailerons (副翼) to help control the way the planes tip as they fly. However, when the Wright brothers flew the first airplane, Flyer 1, over a century ago, they used no ailerons but wires and pulleys that twisted the wood-and-canvas wings, to control the plane.

    Scientists have long sought to develop aircrafts that can alter their wings during flight, just as birds can. However, most previous attempts have failed because they relied on heavy mechanical control structures within the wings. These structures were also complex and unreliable, said Neil Gershenfeld, a physicist and director of the Center for Bits and Atoms at Massachusetts Institute of Technology (MIT).

    The new wing consists of a system of tiny, strong, lightweight modules. The shape of the wing can be changed uniformly along its length using two small motors, which apply a twisting pressure to each wingtip. These wings are covered in “skins” of overlapping strips of flexible material resembling fish sizes. These strips move across each other as the wings alter, providing a smooth outer surface, the researchers explained.

    Wind-tunnel tests of these wings showed that they at least matched the aerodynamic properties of conventional wings, at about one-tenth the weight. Initial tests using remotely piloted aircrafts made with these wings have shown great promise, said Benjamin Jenett, a graduate student at the Center for Bits and Atoms at MIT.

    The new modular structures the scientists developed could be manufactured quickly in mass quantities and then installed by teams of small robots. These modular structures also can be disassembled more easily, making repairs simpler.

    “Still, the first aircraft built using this strategy will not be a passenger jet, ”Gershenfeld said. “Instead, the technology will likely first be tested on unmanned aircraft, leading to drones (无人机) that can fly for a long time, to help deliver internet access or medicine to remote villages and do some rescue works.”

    Mary bought a dress in a women's clothing store.She felt very happy about buying the dress until she got home. Then she remembered she had left her purse at the store.It was the third time that month that Mary had forgotten something important.Mary was angry with herself.She said,“Am I losing it?”

    Emma was teaching a class in mathematics at a college.She began to explain to the students how to solve a very difficult problem.She understood it very well.But somehow,at that moment,she could not explain it.Emma said,“I must be losing it.”

    Americans seem to have a lot of concern about losing it.At least that is what you would think from hearing them talk.They use the expression when they feel they are losing control.It can mean losing emotional control.Or losing the ability to do something.Or losing intelligence.

    Word experts differ about how the expression started.Some believe it came from television programs popular in the 1980s.Others believe it began with psychologists,who deal with how people think,feel and act.

    “We Americans have many concerns about controlling our lives.Perhaps we worry too much,”one psychologist said.“In many situations to say you are losing it eases the tension（不安）.”

    It's healthy.And most people who say they are having a problem are not losing it.

    People may feel more like they are losing it when they are “down in the dumps”.Word expert Charles Funk says people have been feeling down in the dumps for more than 400 years.The word dumps probably comes from Northern European countries.The languages of Denmark and Norway both have similar words.The words mean to fall suddenly.Americans borrowed this saying.And,over the years,it has become a popular way of expressing sadness.

    My daughter Kelly is a cautious person. She needs to warm up to situations, and is hesitant to try new things. When with close friends, she becomes a leader who laughs loudly and chants, "Girls rule, boys drool." But when that comfort zone is not around her, she is shy and nervous.

    This has been challenging for me at times. "Shy" is not a word that I think has ever been used to describe me. But this has been a year of firsts for my girl that has filled her with a new sense of confidence. This year she moved to lap lane in swimming where she was preparing for a swim team. This year she learned to ride a bike without training wheels. And this year she completed her first kids' triathlon(三项全能).

    On Saturday, with a thunderstorm coming soon and my son's birthday party later in the day, we all went out in the dark of the morning for Kelly to participate in her first triathlon. We practiced transitions from swim to bike to run with her, we got all the equipment she'd need, and we kept talking about the race. But as we waited the two hours for the older kids to finish before her turn, she held my leg a little harder and told me she loved me a few too many times. She was nervous but trying to keep it together.

    And then it was her turn. From the second she jumped into the water, my heart soared. My daughter transformed into the most confident human being I had ever seen. She dominated that swim, crushed that bike ride and ran to the finish with the biggest smile on her face.

    I can honestly say that I never felt so proud of someone in my entire life. It wasn't because she did a sport or anything like that. It was because she was afraid of something and conquered that fear with confidence and a fire I hadn't seen before.

    All day I would find myself just looking over at her and smiling. She might be wearing the finalist medal but I felt like I won that day. I won the chance to see my girl shine.

    Shine on, sweet baby.

    China will follow up on its successful mission (任务) to the far side of the moon by sending a probe to Mars next year, one of its top space scientists said Sunday. Wu Weiren, chief designer of China's lunar exploration program, said the red planet was the natural next step. "Next year we'll launch a Mars probe to orbit around the Mars, land on it and probe it," he said. China will also send another probe to take back samples from the moon's surface.

    Wu's comments came as a Mars simulation(模拟) base opened in Qinghai's Qaidam Basin. According to the state-run Global Times, while the red rocky area bears a strikingly similarity to Mars, it's extremely difficult to simulate Mars due to its special natural features and hostile environment—low air pressure, strong radiation and frequent sandstorms, as well as vast differences in geography.

    China didn't send its first satellite into orbit until 1970, by which time America had already landed an astronaut on the moon, but it's been catching up fast. Since 2003, China has sent six crews into space and two space labs into Earth's orbit. In 2013, China successfully landed a rover, Yutu 1, on the moon, becoming only the third country to do so.

    Last December, China landed another probe and a rover, Yutu 2, on the far side of the moon. Progress has been slow going since then: due to the extreme conditions there, the rover often has to hibernate to preserve its capabilities for further exploration, Wu said. "The temperature there is minus 190 degrees Celsius, which all components and parts cannot stand. So we let it sleep for a while, making sure it can spend the night safely. A few days ago, it woke up automatically to work. We've gained lots of data in the past few days, and we're going to make the data known to the world,” Wu said.