【主题分类】汉译英：科技、地铁

【逐句解析】

1.翻译第一句时，根据时态提示词“近年来” 判断应该使用现在完成时；“建设地铁”可译为 construct/build subways。
2.翻译第二句时，“发展地铁……” 既可以像参考译文那样翻译，也可以与第一句合并翻译，把“发展” 删去，用as 连接作目的状语， 译为“...have begun to build subways as this helps reduce...”“交通拥挤”可译为 traffic congestion或 traffic jams；“空气污染”可译为 air pollution。
3.翻译第三句时，“具有……的优点” 既可以译为 has the advantages of...， 后面的“安全、快捷和舒适”译为名词safety， speed and comfort， 也可以译为系表结构， 即“The subway is safe, fast and comfortable” 。
4.翻译第四句时，“选择地铁作为”可以翻译为choose the subway as；“上班或上学” 译为介词短语 to work or school；“主要交通工具” 可译为 the main/major means of transportation。
5.翻译第五句时，根据时态提示词“正”判断使用现在进行时；“乘坐地铁” 可译为 take the subway 或 by subway;“……正变得越来越方便”这个句式一般不译为 sth. is becoming increasingly convenient，而是译为 it is becoming increasingly convenient to do sth...。
6.翻译第六句时，根据语境，“卡” 指的是“交通卡”，因此译为 transportation card 更准确。
7.翻译最后一句时，“老年市民” 可译为 elderly citizens 或 senior citizens；“免费乘坐地铁”可译为 take the subway for free 或 have free access to the subway。 

【参考译文】

In recent years, more and more cities in China have begun to build subways. The development of subways can help reduce traffic congestion and air pollution in cities. The subway has the advantages of safety, speed and comfort. A growing number of people choose the subway as the main means of transportation to work or school every day. Nowadays, it is becoming increasingly convenient to take the subway in China. In some cities, passengers can use a transportation card or mobile phone to take the subway. Many local elderly citizens can also take the subway for free.