in the garden for an hour, the girl suddenly realized she had forgot locking her car door

网友回答

A. Reading
B. To read
(答案→)C. Having read
D. To have read
解析：read的逻辑主语是句子的主语the girl , 且两者之间为主动关系, 所以用ing形式作状语。又根据for an hour可知，read已持续了一段时间，即read先于realized，故要用ing形式的完成式作状语。