referring

例句：

1. 1. When I mentioned the topic at the meeting, he didn't seem to know anything about it.
   我在会议上提到这个话题时，他似乎对此一无所知。
2. 2.He referred to his notes when explaining the problem.
   他在解释问题时提到了他的笔记。
3. 3.The teacher referred to the textbook while explaining the lesson.
   老师在讲解课程内容时提到了教科书。