——I think the book is as interesting as it is instructive．
—— It could never be ．It is well worth reading．
A. as true
B. true
C. the truest
D. truer
网友回答
A. as true
B. true
C. the truest
(答案→)D. truer
解析：考察形容词用法。本句中使用了形容词的比较级和否定词连用，表示最高级的含义。句意：—我认为这本书既有趣又有教育意义。—非常正确。十分值得购买。根据句意说明D正确。