The last four chapters have been concerned with good teaching and effective learning. But however good the teaching and however effective the learning, there will always be a place for remedial work of one kind or another because it is beyond the capacity of a human being to absorb perfectly and retain indefinitely everything he is presented with. Hence, from one point of view, every learner needs remedial teaching after the first lesson. It is unfortunately not uncommon to find a student who is quite incapable of using the present simple tense accurately at the end of the first year of English, even though it has been one of the main teaching points. Before considering what can be done about this sort of situation, it is worth looking first at some of the possible reasons for error.