When she was alone at home，Mary needed a friend .
A. playing with
B. having played with
C. with whom to play with
D. with whom to play
网友回答
A. playing with
B. having played with
C. with whom to play with
(答案→)D. with whom to play
解析：with whom to play为“介词+关系代词+不定式”结构在句中作定语,其相当于一个定语从句(with whom she could play)。