答案：A

题目分析：句意：这就是那个他在会议上解释的由于工作粗心的原因吗？explained at the meeting for his carelessness in his work这是定语，修饰the reason，它与explain之间是被动关系，故用过去分词。如果用定语从句必须用关系代词做explain的宾语，用that或which都行。故选A。

点评：本题较难。非谓语动词是近几年高考的热点，本题是对已学知识点的回顾，需要考生能够理解该题的语言环境，进而作出正确的判断。会判断非谓语动词与它的逻辑主语之间是什么关系，需要考生掌握非谓语动词的不同形式的用法区别等。这里学生误选D，认为是定语从句。

即学即练：The government plans to bring in new laws _____ parents to take more responsibility for the education of their children. 

A. forced            B. forcing            C. to be forced         D. having forced 

解析：B。现在分词短语作后置定语，修饰new laws ,相当于which forces ……...