Question

This math problem is___that one

A .so easy as B. as difficult as C.much difficult than D.less easier

Answer 1

B
as……as…… 和……一样

追问

为什么不是A或D（D后少了than)

追答

A选项不能，除非前面是否定句，这个搭配的结构是not so...as， 就是说，以下说法是正确的：
This problem is as difficult as that one
This problem is not so easy as that one.

而D选项的easier 已经是比较级，不能加less