题目：
_____ in the queue for half an hour, the old man suddenly realized he had left the cheque in the car.[ ]
A. Waiting
B. To wait
C. Having waited
D. To have waited
答案：
答案：C
_____ in the queue for half an hour, the old man suddenly realized he had left the cheque in the car.[ ]
A. Waiting
B. To wait
C. Having waited
D. To have waited
答案：C
