问题补充:
Allen followed his customer across the yard and stood on the step of the house, two shopping bags.
A. lifted
B. having lifted
C. to lift
D. lifting
答案:
A. lifted
B. having lifted
C. to lift
(答案→)D. lifting
解析:考查非谓语动词。lifting 在这里做伴随状语,动作与位于动词同时发生。句意:艾伦跟着他的顾客穿过院子,站在房子的台阶上,拎着两个购物袋。所以选D。