问题补充:
in the garden for an hour, the girl suddenly realized she had forgot locking her car door.
A. Reading
B. To read
C. Having read
D. To have read
答案:
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。