in the ticket hall for almost an hour I suddenly realized I had left my ID card home.A. T

问题补充：

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

答案：

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。