----Which is to understand, this book or that book?
---- I think both of them are quite easy.
A. difficult
B. more difficult
C. the most difficult
D. much too difficult
网友回答
A. difficult
(答案→)B. more difficult
C. the most difficult
D. much too difficult
解析：句意：哪本书理解起来更难呢，这本书还是那本书？我觉得这两本书都很容易。句中有this book or that book表示两者进行比较，用比较级，故选B