You find that you can't make your students learn a topic the way you want because of wide gaps in their pre-requisite learning. What would you do?
AGive up the effort as the gaps are too wide to be filled within the short time available
BAsk the parents to arrange for extra tuition in the pre-requisite areas
CIdentify the gaps and arrange for providing compensatory education programmes
DUse the teaching time more profitably for teaching other new topics