In 1971, China’s first subway line in Beijing was formally put into operation. By December   2017, there were 171 subway lines stretching over 5,083 km in 35 cities on the Chinese mainland. Currently, China has the longest urban railway network in the world, which is predicted to surpass 6000 km by 2020.

The rapid development of China’s urban railway system reflects the country’s growing economic strength. The system has experienced the fastest growth over the past 15 years due to the investment of wealth accumulated from the reform and opening up in urban infrastructure construction. An urban railway system is expensive to build, with one kilometer of subway costing approximately 700 million yuan ($110 million). A city without economic strength cannot develop such an expensive system.

The progress in urban railway construction technologies has also contributed to the fast expansion of the infrastructure. Subway construction involves building underground tunnels, laying rails, manufacturing trains and the operation and management of subways. It is a systematic project which not only covers traditional infrastructure building but also modern electronics and information technology. China s railway construction technologies are the best in the world, with Chinese subway trains now exported to developed countries including the United States.

The expansion of Chinese cities has made it necessary to develop urban railway systems. Since the start of the reform and opening up, a large number of people have migrated to cities and the number of private cars has increased dramatically, resulting in serious traffic congestion. Building subways has become an important way to solve this problem.

This year marks the 40th anniversary of the launch of China’s reform and opening up, and the rapid development of China’s urban railway system exemplifies the achievements made by the policy. As China furthers its opening up, it will continue to maintain steady and rapid economic growth and railway systems will be available in more and more cities.

Jennifer, a senior high school student, was driving the old blue sedan(轿车) owned by her father. She lived on a farm about ten miles away from downtown and used the car back and forth every day.

Jennifer had driven into town that night to see a basketball game between Rockets and Warriors. Now she was on her way home, thinking about the game-winning shot by Harden. As she pulled away from the stadium, she noticed a red pick-up truck follow her out of the parking lot. A few minutes later the truck was still behind her.

“I guess we're going in the same direction,” she whispered to herself. Anxious and suspicious, she began to watch the truck in her mirror. When she changed her speed, the driver of the truck changed his speed too! When she passed a car, so he did.

Then he turned on his high beams, flooding her car with light. He left them on for almost a minute. “He probably wants to pass me,” she tried to comfort herself. But this time she was becoming uneasy. Usually, Jennifer drove home over a back road. It was a narrow and bumpy country road with no few lights, so not too many people went that way. But when she turned onto that road, so did the truck.

“I’ve got to get away from him,” she was seized with sudden trembling and became deathly pale, feeling cold sweat flowing down her back, and without a second thought, Jennifer began to slam on the gas and picked up her speed. Then he turned his high beams on again. After a minute, he turned them off. Then he turned them on again and off again.

She changed gears(档位) and drove even faster, but the truck driver stayed right behind her. Then he turned his high beams on again. Once more her car was ablaze(明亮的)with light. “What is he doing?” she wondered. “What does he want?” Then he turned them off again. But a minute later he had them on again, and he left them on.

At last Jennifer pulled into her driveway, and the truck pulled right behind her.

The driver of the truck explained that the man slipped into the girl’s car just before she left the parking lot.

Nowadays, cars have become a very common vehicle in our life. As the most important transport, cars have improved our modern life in many ways. However, cars also bring about so many problems for people, which should be given more attention than any time before.

Cars give people the ability to travel to any place they like. Many people begin to travel frequently. This helps people connect with each other better than before. A more obvious influence from cars is the large number of jobs that they create. Jobs in several fields open up thanks to cars, such as jobs in car factories, gas stations and highways. This is a huge positive influence on society because they greatly reduce the unemployment rate.

At the same time, the problems that cars cause seem to be more and more serious. A mass use of cars is bound to have some negative consequences. The widespread use of cars has led to serious traffic jams in cities. They have resulted in a reduction in the use of public transportation in many cities. The need to use and develop public transportation has been much discussed and confirmed. And also, car accidents create a number of injuries and deaths. There are hundreds of thousands of them worldwide every year. Gas let out from the engines of cars pollutes the air in cities around the world. Air pollution creates serious health problems and causes many people to die from it. It has become one of the most serious problems today. Efforts to develop pollution-free engines may be the final solution to this problem.

In conclusion, people should not only enjoy the benefits of cars, but also aim to deal with the problems cars have created. At the same time, the government should improve city traffic systems, encourage people to use public transportation, make efforts to improve road safety and encourage the usage of fuels that are low in pollutants. Only in these ways can the benefits of cars outweigh their harmfulness.