What do you use to unlock your cellphone? A password? A fingerprint? Or simply a glance?

    On September 12, 2017, Apple introduced its iPhone X, which has an eye-catching feature—Face ID.

    With Face ID, Apple says, you can unlock your new iPhone by just looking at it. It is powered by a so-called TrueDepth camera system built into the front of the iPhone X.

    When the camera system sees a person's face, it uses 30,000 unseen dots to “map” the shape and outline of the face. A mathematical model of the face will then be created and stored in the phone.

    The next time the person looks at the iPhone X, the same dots are mapped onto his or her face and compared to the stored model. If the two match, then the phone unlocks. This happens in less than a second.

    Apple says the system is smart. If you change your hairstyle, put on sunglasses or makeup, or use the phone in the dark, Face ID still works.

    Although the technology sounds fancy, there are still concerns. For example, will Face ID work for twins?

    According to Apple, the chance of others to unlock your iPhone X using Face ID is one in a million. Face ID can tell the difference between twins, but the error rating（出错率）rises. So one would need to set a password then.

    Apple also emphasizes that Face ID only unlocks when you stare at it. It is what Apple calls “attention aware”. So the phone won't unlock if you are just glancing at the phone for the time. It won't work either if someone puts the phone at your sleeping face or your photo.

    I first met Paul Newman in 1968, when George Roy Hill, the director of Butch Cassidy and the Sundance Kid, introduced us in New York City. When the studio didn't want me for the film - it wanted somebody as well known as Paul - he stood up for me. I don't know how many people would have done that; they would have listened to their agents or the studio powers.

    The friendship that grew out of the experience of making that film and The Sting four years later had its root in the fact that although there was an age difference, we both came from a tradition of theater and live TV. We were respectful of craft(技艺)and focused on digging into the characters we were going to play. Both of us had the qualities and virtues that are typical of American actors: humorous, aggressive, and making fun of each other - but always with an underlying affection. Those were also at the core(核心)of our relationship off the screen.

    We shared the brief that if you're fortunate enough to have success, you should put something back - he with his Newman's Own food and his Hole in the Wall camps for kids who are seriously ill, and me with Sundance and the institute and the festival. Paul and I didn't see each other all that regularly, but sharing that brought us together. We supported each other financially and by showing up at events.

    I last saw him a few months ago. He'd been in and out of the hospital. He and I both knew what the deal was, and we didn't talk about it. Ours was a relationship that didn't need a lot of words.

    In the future we might live somewhere other than Earth, like Mars. Some people ask how this will be possible. Well, Mars is in fact a lot the same as the earth. The days are almost the same as those on the earth. However, the two planets vary in temperature.

    Since there is mostly carbon dioxide on Mars, it would be quite difficult for a human to just land on it. So, special types of homes and space suits have to be designed. The space suits should be almost like the ones astronauts use now, and except that they have to be warmer so that the astronauts can survive the cold temperatures. The space suits must also be able to withstand (承受) high pressure and potentially dangerous radiation that can kill.

    The houses should be similar to our homes today with a slight difference. All of the houses and other buildings should be built inside a large dome (圆顶状物) or bubble. The domes should be made out of glass, and would also be able to prevent radiation from affecting the people inside. The domes will be connected to a machine (like plants which turn carbon dioxide into oxygen).

    With Mars' population growing, how would the people on its surface get fresh food and water? Just like humans use domes, they can also use domes to grow plants. However, the domes where the plants are grown must be built to expand. Once we upgrade the domes to a larger size then we can grow more food by cultivating (种植) more plants. To get the food or come in connect with other domes, there will be long narrow tunnels like roads that connect to each dome separating them by several doors so that the pressure in each dome can remain the same.

    On Mars, so many other things are available to us. As humans, we can have access to rare and fairly expensive metals that aren't very easy to get hold of on Earth, and a colony on Mars enhances (提高) our chances of finding these metals. So when someone here on Earth says that going to Mars is impossible, please tell them that they'll never know it until they try and they may try very soon. After all it's our future. Why not make it on Mars?

    British writer John Donne once said: “No man is an island; every book is a world.” As an enthusiastic reader, I can't agree with the latter part of the sentence more. Every summer, I endeavor to find some peaceful places where I can attack some classics without being disturbed. Thomas Hardy wants to live far from the madding crowd. I am no friend to chaos, either.

    I read George Orwell's 1984 in a New England beachside cottage with no locks on the doors, no telephones or televisions in the rooms. 1984 is a good book that needs deep reflection. Attempting Sound and Fury lying on the bed of a poorly-occupied motel, however, was less fruitful: I made it through one and a quarter volumes, but then my eyelids were so heavy that I couldn't keep them open.

    But this summer I find myself at a loss. I'm not quite interested in J.D.Salinger, say, or Frankenstein. There's always War and Peace which I've covered some distance several times, only to get bogged down in the “War” part, set it aside for a while, and realize that I have to start over from the beginning again, having forgotten everyone's name and social rank. How appealing to simply fall back on a favorite—once more into The Call of the Wild or Alice in the Wonderland, which feels almost like cheating, too exciting and too much fun to properly belong to serious literature.

    And then there's John Steinbeck's The Grapes of Wrath. This title does not amaze but confuse. We're never short of sour grapes, but we've never heard of angry grapes. Anyway grapes are my favorite fruit of summer. These stone fruits can always make me feel cheerful and peaceful all at once.

    I'M Pei, the Chinese-American, who was regarded as one of the last great modernist architects, has died at the age of 102.

    Although he worked mostly in the United States, Pei will always be remembered for a European project: His redevelopment of the Louvre Museum in Paris in the 1980s. He gave us the glass and metal pyramid in the main courtyard, along with three smaller pyramids and a vast subterranean (地下的) addition to the museum entrance.

    Pei was the first foreign architect to work on the Louvre in its long history, and initially his designs were fiercely opposed. But in the end, the French — and everyone else — were won over. Winning the fifth Pritzker Architecture Prize in 1983, he was thought as giving the 20th century "some of its most beautiful inside spaces and outside forms … His talent and skill in the use of materials approach the level of poetry."

    After studying architecture at the Massachusetts Institute of Technology and Harvard, Pei set up his own architectural practice in New York in 1955.

    Designing the John F. Kennedy Presidential Library & Museum in 1964 established him as a name. His East Building of the National Gallery of Art in Washington in 1978 changed people's ideas of a museum. The site was an odd trapezoid (梯形) shape. Pei's solution was to cut it in two. The resulting building was dramatic, light and elegant — one of the first crowd-pleasing cathedrals of modern art.

    Though known as a modernist, and notable for his forms based on arrangements of simple geometric (几何的) shapes, he once urged Chinese architects to look more to their architectural tradition rather than designing in a western style.

    In person, I.M. Pei was good-humored, charming and unusually modest. His working process was evolutionary, but innovation (创新) was never an intended goal.

    "Stylistic originality is not my purpose," he said. "I want to find the originality in the time, the place and the problem."

    Moving flight times from night to day could reduce air travel's contributions to global warming, a new study suggests. Scheduling more (lay time flights may reduce the influence of contrails ——the visible lines of white steam that many planes leave behind them in the sky.

    The role of contrails in climate change is still being studied, but some scientists believe they contribute to the greenhouse effect by trapping heat in the atmosphere.

    Nicola Stuber, first author of the study, suggests that contrails' overall impact on climate change is almost as big as that of aircraft^? s carbon dioxide emissions (排放)over a hundred-year period. Aircraft are believed to be responsible for 2-3% of human carbon dioxide emissions. Like other high, thin clouds, contrails reflect sunlight back into space and cool the planet. However, they also trap energy in the atmosphere and increase the warming effect.

    Stuber and other scientists believe that the effect of the contrails is big. "On average, the green-house effect controls the effects of contrails, said Stuber, a meteorologist at England's University of Reading." The warming effect is far greater for contrails left by night flights," Stuber added. "The cooling effect only happens (luring the day when the sun is up. During the night the greenhouse warming is no longer balanced and that is why the contribution of night-flight is so large."

    Most commercial airline traffic occurs during daylight hours. For example, only one in four United Kingdom flights is a night flight, but those flights create some 60% of the warming created by contrails, the study reports.