Many cultures have different ideas about why people catch colds. For example in the United States, some people think that you can catch a cold if your feet get cold. So, mothers tell small children to wear warm boots in the winter. In other places, including parts of the Middle East, some people believe that strong winds cause colds. So, on trains and buses, people usually don't like to sit next to open windows. In parts of Europe, some people think that wearing wet clothes will give you a cold. They say that after you go swimming, you should quickly put on dry clothes. Today, scientists know that colds are caused by a virus（病毒）. But the old ideas are still very strong, and many people still follow them to avoid（避免）getting ill.

    The street food stands（摊）are very popular in Korea . They take their name from the two kinds of hot foods they sell : Dukbokgi and Odeng .

    Dukbokgi is a spicy hot food made of rice cakes and some vegetables . These rice cakes are finger-shaped . They are white , and they are about ten centimeters in length（长度）. They are mixed with sliced vegetables in a pan with a spicy red dressing（调料）. Fifteen minutes later , they are ready to eat . Odeng is made of ground fish . It comes in many shapes : some are square（正方形）, others are round , and still others are stick style . You can buy big or small ones . At these food stands , you can also eat Odeng , which has been boiled in a pot . It is served on a long stick so can eat it easily .

    The food sold at these stands is not expensive , compared to what other foods in Korea cost . Each Dukbokgi and Odeng costs about twenty to fifty cents , depending on the owner .

    Each food stand has its own recipes（菜谱）for its food ; for example , some like to add sugar or other special ingredients（材料）in the food . Usually , there is just one owner , but if the food stand is big , there may be two or three owners .

    When I was an elementary school student , I used to stop at street food stands every day after school to eat street food because I like it so much .

    Before you go to another country it is a great help if you know the language and some of the customs(风俗)of the country. When people meet each other for the first time in Britain, they say" How do you do?" and shake hands (握手). Usually they do not shake hands when they just meet or say goodbye. But they shake hands after they haven't met for a long time or when they will be away from each other for a long time. Last year a group of German students went to England for a holiday. Their teacher told them that the English people hardly shake hands. So when they met their English friends at the station, they kept their hands behind their backs. The English students had learned that the Germans shake hands as often as possible, so they put their hands in front and got ready to shake hands with them. It made both of them laugh.

    Stonehenge means "hanging stones". They stood in a circle, with 30 more stones lying on top to form a ring of rocks. There was also an inner circle built with similar stones. The stones set up in a trilithon(巨石牌坊) pattern.

    A trilithon is made of two stone pillars with a stab of rock laid across the top. The stones weigh up to 20 tons each. People wonder how the huge rocks were placed that way.

    Historians agree that Stonehenge was built in three different stages. The first stage took place about 5, 000 years ago. At that time, a large circular earth wall was made. Historians believe the wall was dug and cut with tools made form anglers(鹿角) of red deer. The earth wall was about 98m in diameter(直径) a 5-meter-tall stone was placed near the center. Then, they had to transport the large blue stones (up to 4 tons) 384 kilometers to Stonehenge. Experts think they might be moved across ice and snow. The ground in winter in this area is usually full of ice and snow, making it easier to move the rocks. The next task was to stand the stones up. The most difficult task was putting the top stones in place. Each one of these tasks took a lot of planning and a lot of strength, but the workers of Stonehenge were excellent builders.

    Why was the monument built? Some scientists think it's a burial ground. There are over 400 graves (burial sits) nearby. A man was buried with two gold earrings which are the oldest gold ever found in Britain (dated to 2470 BC). Others think Stonehenge was built by early astronomers. Scientists believe that when a person stands in the center of the monument, the changing of seasons can be seen. Certain stones mark the location of the rising and setting moon in midwinter. Other stones mark the rising and setting sun in midsummer. The ancient people held religious ceremonies on these days. These ceremonies probably asked the gods to bring good weather for crops and to protect the people from bad weather.

    Stonehenge is an engineering success. Thousands of years later, it still stands. As a calendar, Stonehenge is very accurate. It shows that early people had a deep understanding of the movements to the sun and the moon. They didn't have machines or computers, but Stonehenge shows people could do many things using only their muscles and their brains.