问题
单项选择题
The book is borrowed from the library, so you ______ your children put dots and lines here and there.
A．should have left
B．ought not to have let
C．needn't have let
D．mustn't have let
答案
参考答案：B
解析： should have done与ought to have done结构用法相同，表示应该做而没有做，否定形式为ought not to have done，表示不该发生的事却发生了，所以B选项是正确答案。needn't have done表示不必做的事情却做了，不合题意。mustn't have done表示对过去的事做出否定性的猜测。should have left意义正好相悖。
