由题干中的 in big modem stores 定位至第一段第六、七句:At the most cutting-edge retail stores—Victoria Beckham on Dover Street, for instance—you don’t go and stand at any kind of cash register when you decide to pay. The staff are equipped with iPads to take your payment while you relax on a sofa.

详解：事实细节题。第一段第六句举例说明在最前沿的商店里人们如何付款。第七句提到，店员都配有平板电脑，顾客在沙发上休息时就可以付账。由此可知，在大型现代商店里，商业交易是通过电子设备完成的。