翻译 近年来，中国有越来越多的城市开始建设地铁。发展地铁有助于减少城市的交通拥堵和空气污染。地铁具有安全、快捷和舒适的优点。越来越多的人选择地铁作为每天上班或上学的主要交通工具。如今，在中国乘坐地铁正变得越来越方便。在城市里，乘客只需要卡和手机就可以乘坐地铁。许多当地老年市民还可以免费乘坐地铁。

   In recent years, more and more cities in China have begun to build subways. The development of metro can help reduce traffic congestion and air pollution in the city. Metro has the advantages of safety, speed and comfort. More and more people choose subway as the main means of transportation for going to work or school every day. Nowadays, it is becoming more and more convenient to ride the subway in China. In cities, passengers only need cards and mobile phones to take the subway. Many local elderly residents can also take the subway for free.