The teacher told the students that they--keep silent in class all the time.

题目

The teacher told the students that they--keep silent in class all the time.
A.ought to not B.ought not to C.ought not to have D.can't选哪个,怎么翻译,

答案

选C：
翻译为：老师告诉学生在课堂上不应该一直都保持沉默.
should／ought to＋should／ought to＋have＋过去分词”既可表示本该做而事实上没有做的事,也可以表示惊讶、赞叹等情绪.