in the ticket hall for almost an hour, I suddenly realized I had left my ID card home.
A. To wait
B. To have waited
C. Waiting
D. Having waited
网友回答
A. To wait
B. To have waited
C. Waiting
(答案→)D. Having waited
解析：考查非谓语动词。因为wait这个动作发生在realize这个动作之前，又因为主句的主语I与wait之间是主动关系，故要用现在分词的完成式，答案为D。