So far no life has been found outside the earth, but while some scientists are a

题型：不详难度：来源：

So far no life has been found outside the earth, but while some scientists are actively searching for living things in outer space, others firmly believe there ____ .

A．mustn’t be

B．may not be

C．can’t be

D．won’t be

答案

C

解析

考查情态动词。mustn’t不表示否定推测，may not“可能不”，可能性没有can’t大；won’t“不会”，不表示推测。根据firmly可知，其他人坚信不可能存在外太空生物。故选C。