When the Normans built their first simple wooden castles in England，they built them on the top of small hills.The first permanent castles were made of stone and built with thick walls.The main building was usually surrounded by walls which overlooked the moat (护城河)．

     The entrance to the castle was usually over a drawbridge (吊桥) leading to the main gatehouse.The drawbridge could be raised or lowered and an iron grille (栅栏) could be lowered to shut off the entrance to the gatehouse.

     As time went on，the castle builders became more advanced in their techniques.Instead of building a strong central building and surrounding it with walls of lesser strength，they thought out the idea of surrounding a central area with huge walls which could contain all the main rooms of the castle.These walls usually had many towers and these towers were really a series of main buildings along the castle walls.In building these castles they used hill sites whenever possible in order to give the castle a better position.Because the outside world was shut off by a barrier or curtain of defences，they are called “curtain wall” castles.

     With the passing of time there was less need to build strong castles and nobles built manor (庄园) houses.These manor houses often had battlements and iron grilles，but they were built more for comfort and included many of the conveniences and luxuries of the large houses which were being built in the towns.

     Unfortunately，many English castles were damaged or destroyed completely during the Civil Wars of the 1600s.

    Have you ever run into a careless cell phone user on the street? Perhaps they were busy talking, texting or checking updates on WeChat without looking at what was going on around them. As the number of this new “species” of human has kept rising, they have been given a new name—phubbers（低头族）.

    Recently, a cartoon created by students from China Central Academy of Fine Arts put this group of people under the spotlight. In the short film, phubbers with various social identities(身份) bury themselves in their phones. A doctor plays with his cell phone while letting his patient die, a pretty woman takes selfie in front of a car accident site, and a father loses his child without knowing about it while using his mobile phone. A chain of similar events eventually leads to the destruction of the world.

    Although the ending sounds overstated, the damage phubbing can bring is real.

    Your health is the first to bear the effect and result of it. “Constantly bending your head to check your cell phone could damage your neck,” Guangming Daily quoted doctors as saying. “the neck is like a rope that breaks after long-term stretching.” Also, staring at cell phones for long periods of time will damage your eyesight gradually, according to the report.

    But that's not all. Being a phubber could also damage your social skills and drive you away from your friends and family. At reunions with family or friends, many people tend to stick to their cell phones while others are chatting happily with each other and this creates a strange atmosphere, Qilu Evening News reported.

    It can also cost you your life. There have been lots of reports on phubbers who fell to their death, suffered accidents, and were robbed of their cell phones in broad daylight.

    Japanese researchers say they have developed a new type of glass that can heal itself from cracks and breaks. Glass made from a low weight polymer (聚合物) called “polyether-thioureas” can heal breaks when pressed together by hand without the need for high heat to melt the material.

    The research, published in Science, by researchers led by Professor Takuzo Aida from the University of Tokyo, promises healable glass that could potentially be used in phone screens and other fragile (易碎的) devices, which they say are an important challenge for sustainable (可持续的) societies.

    While self-healing rubber and plastics have already been developed, the researchers said that the new material was the first hard substance of its kind that can be healed at room temperature. The new polymer glass is “highly robust mechanically yet can readily be repaired by compression (压紧) at broken surfaces”.

The characteristics of the polyether-thioureas glass were discovered by accident by a graduate school student named Yu Yanagisawa, who was preparing the material as a glue. Yanagisawa found that when the surface of the polymer was cut, the edges would adhere to each other, healing to form a strong sheet after being manually compressed for 30 seconds at 21℃. Further experiments found that the healed material regained its original strength after a couple of hours.

    Yanagisawa told NHK that he didn't believe the results at first and repeated his experiments several times to confirm the finding. He said, “I hope the repairable glass becomes a new environment-friendly material that avoids the need to be thrown away if broken.”

    This is not the first time a polymer has been suggested as a healable screen for devices such as smartphones. Researchers at the University of California suggested the use of polymer that could stretch to 50 times its original size and heal breaks within 24 hours.

    Smartphone manufacturers have already used self-healing materials in devices. LG's G Flex 2 shipped in 2016 with a coating on its back was capable of healing minor scratches over time, although failed to completely repair heavier damage.

    According to the research conducted by repair firm iMend, over 21% of UK smartphone users were living with a broken screen, with smashed displays being one of the biggest issues alongside poor battery life.

    China is a big country, and there is no simple answer to the question “When is the best time to visit China? ” There are two best times to visit China, depending on your preference.

    October

    Things to do: hike on the Great Wall, photography tour

    Places to visit: Beijing, Xi'an, Shanghai, Guilin, Jiuzhaigou, Chengdu

The best time to go to China is early autumn (October).

    Most of China has warm temperatures, and the summer rains have stopped (apart from around HongKong and Sanya) so it's pretty dry. The autumnn colours are also amazing. It is quiet at tourist attractions for most of the month, as the summer holiday travel crowds have gone. But try to avoid October 1st -7th, which is the Chinese National Day holiday, as attractions, transport and hotels are packed with Chinese tourists and prices go up a lot.

    Late Spring (April to May)

    Things to do: appreciate flowers, Li River cruise, ethnic festivals

    Places to visit: Beijing, Xi'an, Guilin, Huangshan, GuiZhou, Zhangjiajie

    The second-best time to travel to China is probably in April and May, when the flowers are in bloom and the temperatures are warming up. In late spring, temperatures across China are getting into the 20s (℃), except the extreme northwest and northeast. While the North of China is still dry, the summer rains have already begun in the South. This could actually improve the view in the form of mountain fog in mountainous areas like the Li River and the Yellow Mountains.

    Ethnic festivals in GuiZhou are concentrated in April and May, such as the Sisters' Meal Festival. If you are interested in Miao and Dong ethnic cultures, this is a good time to visit.

    Travel prices are average: cheaper than June to October, but more expensive than the lower season from November to March.

    Bored? Lonely? Out of condition? Why not try the SPORTS CENTER?

    TENNIS

    Indoor and outdoor courts. Coaching from beginners to advanced. Children only. Mornings.

    SKIING

    Gentle slopes. 3 levels instructors at weekends and Fridays. Daytime practice.

    8-year-old upwards.

    SWIMMING

    2 pools, heated, Olympic length.

    Women: Tuesday and Thursday.

    Men: Monday, Wednesday and Friday.

    Children: Saturday.

    GOLF

    9 hole practice course. Professional Coaching. Lessons must be booked in advance in daytime. Evening practice. Minimum age — 9 years.

    GYMNASTICS

    Maximum age —18 years.

    Children aged 5-10. Mondays and Wednesdays. 4:00-6:00 p.m.

    10—18 year olds. Friday evenings.

    AND MANY MORE

    Table Tennis, Snooker (台球), Darts (标枪), Café (all day), Bar (lunch time and evenings), Nursery (weekdays and weekends, not evenings).

    Centre open 10:00 a.m.—10:00 p.m. Daily.

    Interested? More details, call 800-1234-5678.

    Long Beach, a 28-mile stretch of beach, lies in southwestern Washington, and it is generally called Long Beach Peninsula (半岛). Communities there take you back to old days of a simple and slow-paced life style. Here, visitors can relax and enjoy the good of total rest.

    Bird Watching

    There are different kinds of birds in Long Beach. It is best if you observe them from a distance and do not try to frighten them. The Southwest Loop Trail Map can be gotten through the Long Beach Peninsula Visitors Bureau Office by calling 1-800-451-2542.

    Horses

    A popular activity in Long Beach is horseback riding. Two businesses in the city of Long Beach offer guided horseback tours along the beach: Back Country Wilderness Outfitters and Skipper's Equestrian Center. You may also bring your own horse. Among the adventures offered with horses is a wagon (四轮马车) ride along the beach, a carriage ride through Sea view or Long Beach, a back country (偏远乡村) packing trip, or a sunset ride by horseback on the beach.

    Camping

    RV (娱乐车) and tent camping aren't allowed on the beach, but there are private camp­ grounds and RV parks in the area, as well as Cape Disappointment State Park. Camp fires are allowed within 100 feet of the beach, but must be away from the dry grass.

    Swimming and Other Activities

    Swimming is allowed, but you must be careful. The waters are very cold and dangerous. Surfing is advised only for experienced surfers. Beach driving is allowed at certain spots on the beach. The speed limit is 25 mph. Building sand castles, digging sand to find something, bicycle riding, and flying kites are also popular activities in the area.

    You can find right hotels easily in the area. Enjoy your trip to Long Beach, Washington!