问题
选择题
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
答案：D
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。