________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

套期保值的实现条件包括（）。

A.期货品种及合约数量的确定应保证期货与现货头寸的价值变动大体相当

B.期货头寸应与现货头寸相反

C.期货头寸作为现货市场未来要进行的交易的替代物

D.期货头寸持有的时间要与现货市场承担风险的时间段对应起来