And London's Transport Authority has promoted the Oyster card, a magnetic payment system that keeps track of where people have been and when.

VOA: standard.2010.04.01

But once you are here, I think with the oyster card and stuff,

但是，一旦你在这儿，我想有了牡蛎卡，

公共交通更方便 - SpeakingMax英语口语达人