为什么选b请逐个选项分析,At last he()finish the work ahead of time.A.could B.was able to C.could have done D.would have been able to

Question

为什么选b请逐个选项分析,
At last he()finish the work ahead of time.
A.could B.was able to C.could have done D.would have been able to

Answer 1

B
最后他成功的提前完成了工作.
could只是表示过去的能力,was/were able to表示成功的做成了什么事情（类似managed to,注意,这个结构考到机会非常大!）,could have done表示实际没有做成一件事,但本来有能力做成的.would have been able to意思和could have done类似.