I told you that
Sometimes students can miss key points in the lecture. I like to try to compare what we are learning to something that we all know about.
This is not an uncommon issue.
What I do is remind the class that we already discussed this issue, but let's review it again. Then go back to again discuss the topic.
I try to thank the person who asked the question by saying something like, "Thanks for asking this question, because it is an important topic, and it's always good to review again the important topics." This puts the class as ease and tells them it's ok to ask question, even if they didn't get something the first time. And, of course, this gives me the opportunity to discuss again a point which obviously was not understood the first time around.
