Question

I ________ work out the problem at first, but after my teacher showed me an example, I ________ get the answer easily.

A．couldn’t; was able to	B．can’t; could
C．wasn’t able to; could	D．was able to; was able to

Answer 1

A

试题分析：句意:起初我不能做出那个问题，但是在老师给我做了例子后，我就很容易地得到了答案。can作情态动词的基本意思是“能,能够”“可以”“可能,会”,可表示体力、智力能够完成一件事情或环境赋予的能力; 也可表示由于环境或其他因素而产生的可能性,只有现在时和过去时两种形式,，它可表示不一定能够做完一件事；而be able to则有多种时态形式。有能力做，并且做完了事情。故选A。
点评：本题难度适中。情态动词是近几年高考的热点，本题在于考查考生be able to 和can /could的区别及不同的用法的掌握情况。
即学即练：The fire spread through the hotel very quickly but everyone _______ get out.
A. had to              B. would            C. could                D. was able to
解析:D。句意:表示过去具体某次“能够”做成某事只能用 was / were able to 而不用could。