An Overview of the English Tense-Aspect System and Its Problem Areas

 Here is a Prezi that works through the differences among the various tenses and aspects of the English grammar system. it includes a summary of major problem areas as well. Below I have extracted a couple of the key thoughts from it. Quotations refer to the second edition of The Grammar Book.

 Bull's Framework makes a valuable contribution to this discussion because it clarifies that errors will typically occur along one of the axises of the appropriate tense. So, while we may often hear present simple and the past simple confused, it would be quite unlikely to find the present simple confused with the past perfect. To speak in The Grammar Book's terms, these are 'boundary problems'; we need clarity at the edges where things get murkiest.

 Related to the chart shown above, Celce-Murcia and Larsen-Freeman note that the bulk of the 'traffic' of our tense usage is located in the upper left corner. To the extent that this is true, we can expect to find the greater number of our boundary problems occurring there. We may assume, however, that similar errors lurk in the other less-trafficked, and thus less-practiced borderlands.