Further to the recent articles about A-level results (A-level students choosing narrower range of subjects after Gove changes, 14 August), I taught A-level students for more than 30 years. In that time, with all those secretaries of state, there was only one change which produced, for my students at least, an improvement. That was the introduction of AS-levels. Before that, many students treated the first year of A-levels as an opportunity for a rest after their GCSEs. The ability to take a fourth subject for one year was invaluable. It was not only the scientists taking a humanities subject, but also the humanities students taking a science, often maths, who benefited. The split in marks should probably have been 30/70% rather than 50/50, but otherwise AS-levels were excellent. Steve Millar Alton, Hampshire