题目内容：

The 2,298-kilometer Beijing-Guangzhou High-speed Railway 1. (official) opened to passengers on December 26，2012. It is the world’s longest high-speed rail route. The 2. (design)speed of the track is 350 kilometers, though speeds during the initial period of operation will be limited to about 300 km/h. The new route cuts the travel time between Beijing and Guangzhou 3.almost two thirds, from 22 hours to roughly 8 hours .On December 1, 2012，not long before the opening of the Beijing-Guangzhou High-speed Railway, the Harbin-Dalian High-speed Railway, 4. first high-speed line ever to cross land that lies frozen for almost half a year, began operations, 5. allows passengers to appreciate the view off the coast from Dalian in the morning, 6. the winter snowscape of frosty Harbin in the afternoon . At present the total 7. (long) of high-speed lines in China 8.(reach) 9,349 km. With four main lines 9. (run) east-west and four north-south, the country’s high-speed train network is the world’s largest. China plans to expand 10. high-speed railway network to 50,000 km by 2020, to cover almost all large and medium-sized cities.