It was not until the subprime loan crisis (次贷危机) ____ great damage to the American financial

system that Americans ____ the severity of the situation. [ ]

A. caused, realized

B. had caused, realized

C. caused, had realized

D. was causing, had realized

票据到期被拒绝付款的，持票人可以对（）行使追索权。

A.出票人

B.背书人

C.汇票的其他债务人

D.委托人