第6题: [单项选择]You ______ him so closely; you should have kept your distance. A. shouldn’’t follow B. mustn’’t follow C. couldn’’t have been following D. shouldn’’t have been following 参考答案:D 答案解析:should的否定形式跟完成时或完成进行时一起使用表示“本来不应该做某事(暗示已经做了该事)”讲。例如:You shouldn’’t have been so naive as to say that