Question

__________ in the queue for half an hour, Tom suddenly realized that he had left his wallet at home．

[　　]

A．

To wait

B．

Have waited

C．

Having waited

D．

To have waited

Answer 1

答案：C
解析：

“汤姆排队半个多小时，突然发现他的钱包忘在家里。”C项是现在分词的完成时，表示从过去某个时刻开始一直持续到谓语动词的动作发生的时间。