It was impossible for the whales to escape and move south --------/?

题目

It was impossible for the whales to escape and move south --------/?
No.it is not .The ice stretched for kilometers aroud them .
A.was it B.was not it C.were they 为什么?impossible不是否定含义吗?

答案

A
im- in- dis- less 等否定的前缀后缀不能当成否定词的