情态动词用法should would could

题目

情态动词用法should would could
john told me that he did a stupid thing yesterday and seemed rather unhappy i can't imagine he _have said that,it was my fault A should B would C could Dmight 答案为C求其他几个选项的解释
should。为什么不是could

答案

should特殊用法,表示“竟然”
如： A gentleman should be so rude at his friend!