economical/iːkəˈnɔmɪk(ə)l/
adj.节省的Going by train is more economical than going by plane.坐火车比坐飞机更节约。
Bicycles are regarded as an economical alternative to buses whose fares have increased 5 times in the past 3 years.自行车被看成是比公共汽车更实惠的交通工具，因为公共汽车票价在最近三年内涨了五倍。
A small car is more economical than a large one, because it uses less petrol.小的汽车比大的节约，因为它耗油较少。