They often to be careful before the road.
A. are, told, cross
B. are, told, across
C. are, telling, crossing
D. are, told; crossing
网友回答
A. are, told, cross
B. are, told, across
C. are, telling, crossing
(答案→)D. are, told; crossing
解析：D“他们经常被告诉过马路时要小心。”，根据句意得知，考查的是被动语态。before在此为介词，后加doing，故选D。