When I was at school my O Level History text book was riddled with Punch cartoons which I never seemed to grasp till I went to University. One of my favourites, when teaching social conditions in the 19C, was that of the little girl in the grocer's who asked for half a pound of margarine (then a new discovery), concluding with the words,
" And Mam says, 'Can you put the cow on it, 'cos she's got company for tea"
It took me ages to explain that one to the kids.