题目内容：

the book is _______that one,but________than that one
diffcult expensive
A.as difficult as,expensive B.as more difficult as C.as difficultas,more expensive D.more difficultas,as expensive

优质解答

the book is _as difficult as______that one,but__more expensive______than that one

追问：

为什么

追答：

前面是同级比较用as...as结构，后面是比较级，用-er+ than，expensive是多音节词，故前面加more。