My 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(傣族人) 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 bike riding 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 ride along the whole Mekong River from where it begins to where it ends. Now she is planning our schedule for the trip.

My sister has one serious shortcoming(缺点). She can be really stubborn(固执的). Although she didn't know the best way of getting to places, she insisted(坚持) 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 hadn't; my sister doesn't care about details(细节). So I told her that the source (源头)of the Mekong River is in Qinghai Province. She gave me a determined look—the 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(呼吸) 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 it we could see that the Mekong River begins in a glacier on a mountain in Qinghai Province. 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. We were both surprised to learn that half of the river is in China. After it leaves China, the Mekong becomes wide, brown and warm. As it enters Southeast Asia, its pace slows. At last, the river delta enters the South China Sea.

A few good friends are talking about their last vacations.