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.

    The Healthy Habits Survey shows that only about one third of American seniors have correct habits. Here are some findings and expert advice.

    This is a photo of a similar car I own. It's a photo of a Skoda Fabia, I drive one too. A young guy also got out of a similar car as I was getting close to mine. I laughed and was prepared to leave. The young guy continued to have a conversation with me.

    He asked me how I found the car. It turned out that it was his first day to drive the car and it was new and it was a gift from his parents and he'd just passed his driving test today! What a coincidence (巧合)!

    Well, this was a special moment for Nicholas. Who gets a new car the day they learn to drive and then drives into a garage and has a talk with a woman who's driving the same model of car? Yes, beautiful synchronicity (同步性) in full view.

    I wanted to make this moment special for Nicholas, and I wanted to gift him something. Thinking on my feet, I thought I'd buy him a lottery ticket (彩票) but it wasn't special enough.

    I got into my car and removed my Guardian Angel key ring which I had attached to my front mirror. It was there to keep me safe. My birthday is on Guardian Angel's Day too, so this is very special to me. I gave it to Nicholas and he was happy to receive it. Nicholas gave me a big hug.

    Nicholas was not an overconfident guy. He also told me his mum was only out of hospital and now he'd be able to help her get about.

I'll order myself another Guardian Angel key ring for my car for fear that my Guardian Angel will not be protecting me without the key ring. As for Nicholas, well, I wish he and his passengers a lifetime of safe driving.

    The Dunning-Kruger effect is a type of cognitive bias (偏见) in which people believe that they are smarter and more capable than they really are. Essentially, low ability people do not possess the skills needed to recognize their own incompetence. The combination of poor self-awareness and low cognitive ability leads them to overestimate their own capabilities. This phenomenon is something you have likely experienced in real life, perhaps at a holiday family gathering. Throughout the course of the meal, a member of your extended family begins spouting off on a topic, boldly announcing that he is correct and that everyone else's opinion is stupid, uninformed, and just plain wrong. It may be plainly evident to everyone that this person has no idea what he is talking about, but he talks continuously, blithely oblivious (忘乎所以) to his own ignorance.

    The effect is named after researchers David Dunning and Justin Kruger, two social psychologists. They found incompetent people are not only poor performers, they are also unable to accurately assess and recognize the quality of their own work. These low performers were also unable to recognize the skill and competence levels of other people, which is part of the reason why they consistently view themselves as better, more capable, and more knowledgeable than others.

    This is the reason why students who earn failing scores on exams sometimes feel that they deserved a much higher score. They overestimate their own knowledge and ability and are incapable of seeing the poorness of their performance.

    “In many cases, the incompetent are often blessed with an inappropriate confidence, encouraged by something that feels to them like knowledge.” Dunning and his colleagues have also performed experiments where they ask respondents if they are familiar with terms related to subjects including politics, biology, physics, and geography. Along with genuine concepts, they added completely made-up terms. In one such study, approximately 90 percent of respondents claimed that they had at least some knowledge of the made-up terms.

    So what can you do to gain a more realistic assessment of your own abilities? Instead of assuming you know all there is to know about a subject, keep digging deeper. Once you gain greater knowledge of a topic, the more likely you are to recognize how much there is still to learn. Another effective strategy involves asking others for constructive criticism. While it can sometimes be difficult to hear, such feedback can provide valuable insights into how others perceive your abilities. Even as you learn more and get feedback, it can be easy to only pay attention to things that confirm what you think you already know. In order to minimize this confirmation bias, keep challenging your beliefs and expectations and seek out information that challenges your ideas.

Are you interested in working with animals? Now here comes the chance. Kirby Wildlife Park has set up the unique Keeper Experience. The fantastic experience is available to anyone over the age of 18 who is reasonably fit. We regret that for health and safety reasons, people who are pregnant, in a wheelchair or suffering from illness cannot take part.

A typical day

9:15 Arrival

9:30 Health and Safety Briefing

10:00 Apes and Monkeys

While cleaning out enclosures(围场), you will find out how to enrich enclosures with novel items and new smells to stimulate the animals' senses and imitate their natural environment.

12:00 Lunch

14:00 Big Cats

You will feed the cats and learn about their nutritional needs. The keeper will give you an introduction to how cats' behavior can be read to get an idea of their welfare and health.

16:30 Meet the Team

Meet more of the staff and learn how you can get further involved with work at the park. Learn about our animal adoption plan, what it takes to be good keeper and where to obtain the right qualifications for a career in animal welfare.

Booking and cancellation

The Keeper Experience is available on Mondays, Wednesday and Fridays throughout the year, and must be booked at least fourteen days in advance. Full payment is needed when booking.

Cancellations must be made more than one week before the event, or you won't receive a full refund.

A team in Europe are working with wood, but not in the usual ways. They are not carpenters（木匠）. Instead, they are scientists exploring how wood can lead to a greener electronic device, a transistor（晶体管）made from balsa wood, whose production releases less climate-warming gas into the air.

Transistors play an important role in computers and other devices. They act like tiny switches to control the flow of electricity. Engineers use them to process and store data. Today's laptops may host billions of them. So they must be tiny—only a little wider than a strand of DNA.

The new transistor being built by physicist Isak Engquist and his team at Sweden's Linköping University isn't as small as those. Big enough to see and hold, it can stand only an electric pressure that pushes electrons along. And it controls a current using charged particles（粒子）called ions.

This new technology shows a "proof of concept" that the idea can work, even if the new device is not yet ready to put into today's electronics. "While it seems large by today's standards, such a transistor still might prove useful for electronics that require low electric pressures," says Engquist.

"The new transistor suggests that future electronic devices might be made in living plants," Daniel Simon, a physicist in the team, says. "Imagine peeling away some bar k from a living tree," he says, "and stamping electronic circuits into the living wood."

In fact, Engquist says, "There are so many ways we can use wood and the components of wood that we would never have thought of." For instance, he can now imagine a wood-based sensor that could monitor crop health, measure pollution or survey a forest for fire risk.