【题目】Nowadays a strange, new dilemma faces Chinese pedestrians: should you help an elderly person who ________ into the street?
A. is falling B. has fallen
C. had fallen D. was falling
在线课程【答案】B
【解析】
试题分析：句意：如今中国行人面临着一种奇怪、新的困境：该不该帮助摔倒在马路上的老人？此处指已经摔倒在地的老人，强调完成，应该用现在完成时，故选B。