My school stood in a big square playground in southeastern South Dakota. One teacher taught all grades, first through eighth. Most grades had only two or three students.

    Our school day started with the flag pledge(宣誓). Then the teacher called one grade at a time to the recitation bench beside her desk. She'd check our work, explain the new lesson, and dismiss us to go back to our own desks and do our new work, all in less than ten minutes per grade.

    At noon we ate lunches we had brought. Our lunches consisted of homemade sandwiches and if we were lucky, dessert. My favorite dessert was a fresh pear, and a piece of Mom's delicious sour cream chocolate cake.

    The annual Christmas program was the most exciting part of the year. We hurried through our lessons during December to allow time to practise poems, songs, and plays.

    A few days before the performance, the school board members borrowed equipment from the town and set up a stage across one side of the classroom. We hung bed sheets for curtains.

    On the evening of the performance, petrol lanterns hanging along the walls cast a warm, though not very bright, light over the gathering crowd. We could hardly contain our excitement as we looked from behind the curtains to wave at our parents.

    On a spring Sunday in a new term, just before the last day of the school term, everyone in the neighborhood gathered for a picnic. Our moms set fried chicken, bowls of salads, and desserts on the teacher's desk and the library table. After the dinner, we played games. One of the school board members brought big buckets of ice cream in the afternoon to top off the picnic. How we looked forward to that treat!

    I was just nineteen years old when I started my first teaching position in a country school with thirteen students. I felt excited, nervous and happy as I prepared my lunch bucket the first morning of the term. I can't remember what kind of sandwiches I packed, but I do remember I put in a fresh pear and a piece of chocolate cake for dessert!

    Before I studied psychology, I used to think that people would laugh when funny things occurred. While I was right about that, I discovered there are lots of other psychological factors that make people laugh other than the funny part of a joke. When someone laughs at a joke, there will usually be more than one reason that makes him laugh—and the more reasons there are, the more powerful the joke will be.

    I was attending a stand-up comedy show in Egypt, and when the man started to make fun of pedestrians crossing streets, everyone laughed their hearts out. The main reason those people strongly laughed was that almost all of them felt angry towards pedestrians who crossed streets carelessly. The joke wasn't only funny, it also made the audience feel that they were right about being angry at those pedestrians. That is, people were laughing both because of the funny joke and because of the happiness experienced as a result of the psychological support they got.

    The better a joke makes a person feel, and the more it includes other psychological factors, the more the person will like it. For example, if you envy one of your friends, and someone tells a joke that is funny and, at the same time, makes your friend seem stupid, then you will probably laugh at it louder than if you weren't jealous of him.

    In short, we don't laugh only when we hear something funny; we also laugh when we experience some kind of happiness that results from the other psychological factors involved in the joke. I strongly discourage making fun of anyone or belittling someone to make someone else laugh. All I want to explain is that if your joke supports a person's emotions, he will certainly like it a lot.

    Listening to audio books(有声读物) is a really terrific way to enjoy all kinds of books during those times of the day when stopping to sit down and read a book is not an option. An audio book gives the listener hours and hours of entertainment or instruction, or sometimes both at the same time. They are great for people of all ages and make a long road trip a more interesting experience, instead of being boring and dull.

    The biggest benefit of an audio book is that it can be listened to anyplace and anytime. It is a favorite companion for people while they are traveling, commuting, exercising, shopping, working in the garden, or even dusting and vacuuming the house. Using headphones with your favorite audio book player allows you to listen to and absorb the information no matter what might be going on around you.

    Even when you are in a situation that is quiet and are able to enjoy a good audio book, there are still advantages of using your headphones. You can often improve your retention(记忆力) and comprehension of the material when you use headphones because they help reduce distractions from other noises and help you focus better.

    There are a number of different audio books these days that people can choose from. There are audio books on CDs, on audio cassettes(盒式磁带) and also as MP3s and any standard CD player, cassette recorder, or MP3 player that you might use to listen to music can function as an audio book player as well.

    No matter which kind of audio book you prefer to listen to, there is an ever-increasing variety of works that you can select from these days. Virtually any subject matter that is contained in printed books will have at least some audio version available as well. However, books on audio cassettes are starting to become rarer.

    Palaces are known for their beauty and splendor, but they offer little protection against attacks. It is easy to defend a large building, but usually these buildings are not designed with the comfort of a king in mind. When it comes to structures that are both beautiful and defensive, the European castle is a big success.

    Castles were originally built in England by the Normans in 1066. They built towers and walls to secure the land they had taken. These castles provided the Normans with a quiet and safe place. They also served as bases of operation for attacks. In this way castles served both defensive and offensive roles. Besides, castles served as offices for governors. Those that were socially beneath the governor would come to report affairs and express their respect. They would address problems, handle business, feast, and enjoy festivities in castles. So castles served as social centers as well.

    The first castles were made from earth and wood, and they were likely to suffer from attacks by fire. Then wooden castles were gradually replaced by stone, which greatly increased the strength of these towers and walls. However, attackers could throw flaming objects into castles through the windows or burn the wooden doors. This led to moving the windows and entrances off of the ground floor and up to the first floor to make them more difficult to access.

    During the Middle Ages, attacks increased in regularity, so castle defenses were updated. Arrow-slits were added. They were small holes in the castle, which allowed defenders to fire without being hurt. Towers were built from which defenders could provide fire on both sides. The towers were connected to the castle by wooden bridges, so that if one tower fell, the rest of the castle was still easy to defend. A lot of rings of castle walls were constructed, so that even if attackers went past one wall, they would be caught on a killing ground between inner and outer walls. All of these increased the defense of castles.

    The end of castles can be attributed to gunpowder. During the 15th century, artillery, a kind of large guns, became powerful enough to break through stone walls. This greatly made the role of castles less effective. Though castles no longer serve their original purposes, remaining castles receive millions of visitors each year who wish to experience the situations of ancient times.

    If you've been in public in the past year or so, chances are you've noticed someone breaking dining etiquette (礼仪) that would seem second-nature to any adult. Why does our dining etiquette seem to be at an all-time low right now.

    "Overall, there is much less feeling about the common good, which means caring about your neighbor—whether at home or in a restaurant," said Steven, who writes articles for USA Today.

    Take the use of cellphone at the table for example. While a 2015 survey by the Pew Research Center found that 38 percent of those surveyed thought it was acceptable to use their phones while dining out, the increasing number of cellphone bans in restaurant shows that restaurants aren't putting up with it.

    However, some look on the growing use of cellphones as a sign that manners change alongside our society.

    "Manners change," said the writer behind a food site The Takeout. "What we consider improper isn't set in stone." She points out the other "rules" that have since become outdated nowadays, like saying "Sir" and "Ma'am," as proof of this change.

    Yes, traditional manners are yet another thing being redefined by youth. "Younger people are growing up in a world with more flexible rules, and this spreads to the dining table," said Daniel Levine, director of global trends consultancy The Avant-Guide Institute.

    Whether you prefer high-end restaurants or a fast-casual meal, the biggest reason behind the decline of manners may just be a numbers game.

    "I believe it is more likely for people to break dining 'rules' because they go out and eat more often," said Diane Gottsman, owner of The Protocol School of Texas. "Years ago, people stayed home and sat around the family table. Today, there are more people in the workforce, which makes it more affordable for socializing and eating out. With new chance comes the possibility for more dining problems."

    Earthquakes strike suddenly at any time of the day or night, but there's no way to tell when. If an earthquake happens, it may cause many deaths, injuries and damage. So you need a good preparation ahead of time. Decide how and where your family will get together if separated. Choose an out-of-state friend or relative that the family members can call after the quake to report where they are and how they are. Know the safe places in each room: under the strong tables, desks, or against inside walls. Keep enough food, water and other things, including a flashlight, a radio, medicines and clothing.

    During the earthquake, you should keep a clear head and never be too nervous to know what to do. Protect your head and neck with your arms. If possible, take a book, a pillow or any other things to protect yourself from falling glass and ruins. If you are indoors, you must immediately lie under any strong furniture. If outdoors, move to an open area away from trees, buildings, walls or power poles. If you are in a narrow valley, move to the centre of it and look up for falling stones. If you are in a car, move to the side of the road and stop the car. Do not stop near buildings, power lines or on or under bridges. Stay in your car until the shaking stops.

    Do not move a badly injured person unless he is in great danger after the earthquake. Do not use the telephone immediately unless there is a serious injury or fire. Turn on your radio for instructions and news reports. Be prepared for aftershocks. If you want to leave your home, post a message inside your home telling your family members where you can be found.