Since 1984,Philadelphia has been cleaning up its act.One by one,graffiti（涂鸦）covered walls are being changed into outdoor art.So far,more than 1,800 murals（壁画）have been painted.Philadelphia now has more murals than any other American city.

    The walls that were once ugly with graffiti are now covered with beautiful pictures of historical heroes and modern art, thanks to the Mural Arts Program(MAP).Its work makes schools and public places attractive,and its citizens very proud.The program began as part of Philadelphia's Anti-Graffiti Network.Jane Golden is the MAP's artistic director."When people ask me what our program is about,"she says,"I answer them with one word: hope." Each year, the MAP offers youth art programs and workshops.Some onetime graffiti writers even help paint MAP murals.

    The MAP's work,says Golden,is all about developing a sense of community（社区）.When a neighborhood requests a mural,the MAP works with the people there to develop a message.Some messages have been "Safe Streets,"Love and Care," and "Peace Walk".

    The MAP receives up to 50 requests for murals each week. Last year, the workers painted 140 murals."The making of a mural enters people's collective memory as an extraordinary, pleasant moment in neighborhood history," says Golden, who began as a muralist in Los Angeles.

    The Winter Olympics are also called The White Olympics. At this time, many colorful stamps are published to mark the great Games. The first stamps marking the opening came out on January 25th,1932 in the United States for the 3rd White Olympics. From then on, publishing stamps during the White Olympics became a rule. During the 4th Winter Olympics, a group of stamps were published in Germany in November 1936. The five rings of Olympics were drawn on the front of sportswear. It was the first time that the rings appeared on the stamps of the White Olympics.

In the 1950's, stamps of this kind became more colorful. When the White Olympics came, the host countries as well as the non-host(非主办方)countries published stamps to mark those Games. China also published four stamps in February 1980, when the Chinese sportsmen began to take part in the White Olympics.

    Japan is the only Asian country that has ever held the White Olympics. Altogether 14,500 million stamps were sold to raise money for this sports meeting.

    Different kinds of sports were drawn on these small stamps. People can enjoy the beauty of the wonderful movements of some sportsmen.

    There are two great trends on parents bringing up children today．First，children are now praised to an unbelievable degree．As Dorothy Parker once joked，American children aren't raised；they are motivated．Children are constantly told how special they are．The second is that children are honed(磨砺) to an unimaginable degree．Parents spend much more time than in past generations on their children's development．

    These two great trends—greater praise and greater honing—combine in close ways. Parents shower their kids with affection，but it is intermingled with the desire to help their children achieve success．Parents are happy when their child studies hard，practices hard，wins first place，gets into a famous college．

The wolf of conditional love is hidden in these homes．The parents feel they love their children in all circumstances．But the children often think differently．They feel that childhood is a performance—on the athletic field，in school and beyond．The shadowy presence of conditional love produces a fear，the fear that there is no completely safe love．

    Meanwhile，children who are uncertain of their parents' love develop a great hunger for it. This conditional love is1ike an acid that affects children's criteria to make their own decisions about their own colleges，majors and careers．At key decision-points，they unconsciously imagine how their parents will react．

    These children tell their parents those things that will bring praise and hide the parts of their lives that won't. Studies suggest that children who receive conditional love often do better in the short run．They can be model students．But they suffer in the long run. They come to hate their parents．They are so influenced by fear that they become afraid of risk．

    Parents today are less likely to demand obedience(顺从) with explicit rules and lectures．But they are more likely to use love as a tool to exercise control. But parental love is supposed to ignore achievement. It's meant to be an unconditional support -a gift that can not be bought and cannot be earned．

    Amazing concept images have shown what homes of the future could look like, as preparations are made for the world's first free from 3D-printed property (房产).

    Experts will build a house called Curve Appeal, which will be 3D-printed off-site before being put together on-site to create two outside walls, a roof and an inside part. These four main sections will then be joined together.

    Although 3D-printed buildings have been made before, this home - to be constructed in Chattanooga, Tennessee, later this year — will be the first of its kind, as it will contain no regular shapes or angles. The house is the creation of the design company WATG, based in London and California. The design for Curve Appeal draws inspiration from the Case Study House program.

    The architects leading the program were famed for constantly pushing the limits in terms of minimalist (极简主义) materials, and trying to create open-plan spaces that focused on enhancing (增强) natural light. In a written statement, a spokesman for WATG said, “Employing many of the same modem design principles, Curve Appeal is the next evolutionary step. It's important that the architecture and the environment work together harmoniously. The chosen site is steps away from the Tennessee River in a beautiful wooded, sunlit area.”

    WATG was awarded the first prize in the Freeform Home Design Challenge in 2016 and given prize money of $ 8,000 to make its plans a reality. The competition was aimed at architects, designers, engineers and artists. Participants were challenged to design a 600 to 800sq ft single-family home that rethinks traditional aesthetics (美学), ergonomics, construction, building systems and structure.

    Over the last year, WATG's Chicago office has been developing their design with Branch Technology. This project is currently underway, working towards breaking ground later this year. Once completed, the Curve Appeal home will have open and light-filled inside living spaces.

    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.