问题补充：
单选题TheygottwofreeticketstoCanada,otherwisethey______abletoaffordtogo.A.wouldn’t have beenB.mustn’t have beenC.wouldn’t beD.hadn’t been
答案：
A解析句意：他们得到了两张去加拿大的免费票，否则他们是绝对出不起旅费的。否则；要不然，后面用would have done表示与过去事实相反的虚拟语气，本句相当于：If they hadn’t got two free tickets to Canada, they would, they wouldn’t have been to afford to go.
