Many of these are idioms, a statement that when translated doesn't make sense, and as an English teacher I teach idioms to 7th graders. Many, many of them haven't heard of most of them. We went over about 60 of them explaining the meaning. Now I catch them using them periodically. I think most of these kids' parents don't even know what a lot of these sayings mean, if they have even hard of them. This is always one of my favorite units to teach.