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

試題分析：句意:起初我不能做出那個問題，但是在老師給我做了例子后，我就很容易地得到了答案。can作情態(tài)動詞的基本意思是“能,能夠”“可以”“可能,會”,可表示體力、智力能夠完成一件事情或環(huán)境賦予的能力; 也可表示由于環(huán)境或其他因素而產生的可能性,只有現(xiàn)在時和過去時兩種形式,，它可表示不一定能夠做完一件事；而be able to則有多種時態(tài)形式。有能力做，并且做完了事情。故選A。
點評：本題難度適中。情態(tài)動詞是近幾年高考的熱點，本題在于考查考生be able to 和can /could的區(qū)別及不同的用法的掌握情況。
即學即練：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:表示過去具體某次“能夠”做成某事只能用 was / were able to 而不用could。