Some of the exercises appear to be ones that you have done, but after taking second look, you will find that they are different.
A. 不填; the
B. the; the
C. the; a
D. the; 不填
网友回答
A. 不填; the
B. the; the
(答案→)C. the; a
D. the; 不填
解析：考查冠词。you have done这个定语从句修饰的ones,加the表示限定。后一空a second look表示再次看。句意：一些练习貌似跟以前做过的一样，但你再次细看才发现它们并不相同。