live in the mountains of the eastern USA speak with an older kind of English dialect. When Americans moved from one place to another, they took their dialects with them. So people from the mountains in the southeastern USA speak with almost the same dialects as people in the northwestern USA. The USA is a large country in which many different dialects are spoken. Although many Americans move a lot, they still recognize and understand each others dialects.THE OXFORD ENGLISH DICTIONARYYou may think that English dictionaries have been used for many, many centuries. The spelling of English has always been a problem but it was more of a problem in the days before a dictionary. Then people could spell word in different ways which you might find it interesting. But it made reading English much more difficult. So dictionaries were invented to encourage everybody to spell the same. In fact, an English dictionary like the kind you use today wasnt made until the time of the late Qing Dynasty. There men did most of the important early work on dictionaries: Samuel Johnson, Noah Webster, and James Murray. These men spent nearly all of their lives trying to collect words for their dictionaries. For them, it wasnt only a job; it was a wonderful journey of discovery. The largest dictionary in the world is the Oxford English Dictionary, or OED for short. The idea for this dictionary came from an important meeting in Britain in 1857. Twenty-two years later, Oxford University asked James Murray to be the editor of its new dictionary. Murray had never been to college. At the age of fourteen, he left his village school in Scotland and taught himself while working in a bank. Later he became a great teacher. After Oxford gave him the job, Murray had a place built in the garden behind his house to do his work. Part of it was one meter underground. In winter it felt like a barn, he had to wear a heavy coat and put his feet in a box to keep warm. Every morning, Murray got out of bed at five oclock and worked several hours before breakfast. Often he would work by the candle light into the evening. Murray hoped to finish the new dictionary in ten years. But after five years, he was still adding words for the letter A! then others went to work with Murray, including his two daughters. He worked on the dictionary until he was very old. Forty-four years later, in1928, other editors finished it. It included more than 15,000 pages in twelve books. And you thought your dictionary was big!Unit 3JOURNEY DOWN THE MEKONGPART 1 THE DREAM AND THE PLANMy name is Wang Kun. Ever since middle school, my sister Wang Wei and I have dreamed about taking a great bike trip. Two years ago she bought an expensive mountain bike and then she persuaded me to buy one. Last year, she visited our cousins, Dao Wei and Yu Hang at their college in Kunming. They are Dai and grew up in western Yunnan Province near the Lancang River, the Chinese part of the river that is called the Mekong River in other countries. Wang Wei soon got them interested in cycling too. After graduating from college.we finally got the chance to take a bike trip. I asked my sister, Where are we going? It was my sister who first had the idea to cycle along the entire Mekong River from where it begins to where it ends. Now she is planning our schedule for the trip. I am fond of my sister but she has one serious shortcoming. She can be really stubborn. Although she didnt know the best way of getting to places, she insisted that she organize the trip properly. Now, I know that the proper way is always her way. I kept asking her, When are we leaving and when are we coming back? I asked her whether she had looked at a map yet. Of course, she hadnt; my sister doesnt care about details. So I told her that the source of the Mekong is in Qinghai Province. She gave me a determined lookthe kind that said she would not change her mind. When I told her that our journey would begin at an altitude of more than 5,000 metres, she seemed to be excited about it. When I told her the air would be hard to breathe and it would be very cold, she said it would be an interesting experience. I know my sister well. Once she has made up her mind, nothing can change it. Finally, I had to give in. Several months before our trip,Wang Wei and I went to the library. We found a large atlas with good maps that showed details of world geography. From the atlas we could see that the Mekong River begins in a glacier on a Tibetan mountain. At first the river is small and the water is clear and cold. Then it begins to move quickly. It becomes rapids as it passes through deep valleys, travelling across western Yunnan Province. Sometimes the river becomes a waterfall and enters wide valleys. We were both surprised to learn that half of the river is in China. After it leaves China and the high altitude,the Mekong becomes wide，brown and warm. As it enters Southeast Asia, its pace slows. It makes wide bends or me