It is believed that if a book is it will surelythe reader.A. interested …interestB. inter

问题补充：

It is believed that if a book is, it will surelythe reader.

A. interested …interest

B. interesting …be interested

C. interested …be interesting

D. interesting…interest

答案：

A. interested …interest

B. interesting …be interested

C. interested …be interesting

(答案→)D. interesting…interest

解析：动名词作表语时, 表示主语的内容；现在分词作表语，表示主语的特征或性质。