单选题
"The lecturer was a tall thin man with white hair.""Then it（ ）Dr.Firld because he is short and fat.It Dr.Jones;he is thin."
Acan’t be...must be
Bcouldn’t have been...might have been
Cmust be...can"t be
Dcan"t have been...must have been
正确答案
答案解析
该题考查情态动词用法。根据题干可排除A，C选项（must be，can"t be分别表示现在的肯/否定推测），而B选项中的might have been表示可能已经做成某事。故选D。表示对过去的否/肯定推测。