问题补充:
We finish it ahead of time, though it was such a tough task.
A. could
B. would
C. were able to
D. ought to
答案:
A. could
B. would
(答案→)C. were able to
D. ought to
解析:考查情态动词。could 能够,would 会,were able to 成功做成什么事,ought to 应该,句意:我们成功的提前完成了任务,虽然这是一个如此艰难的任务。所以选C。