四、翻译下列短文：

       The 1,956-kilometer Qinghai-Tibet Railway is the world's highest and longest plateau railway with 960 kilometers above the altitude of 4,000 meters. It is the first railway in Tibet, which not only greatly shortens the traveling time to Tibet, but considerably promotes the economic development of Tibet. Now a large number of people choose to visit Tibet by train so that they have the opportunity to admire the beautiful scenery along the way.