Wefinish it ahead of time though it was such a tough task.A. couldB. wouldC. were able to

问题补充：

Wefinish 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：句意：尽管这是一项艰巨的任务，我们还是提前完成了。be able to表示经过一番努力做成某事，符合句意。