A (Advanced) level in England used to be taken at 17/18 years as the final school exam and qualified the student for entry to university and it could be translated as Bachillerato. The problem is that at A level you concentrated on only about three subjects so it was very narrow. To broaden it, a few years ago the government introduced AS and A2 levels which together make up an A level. The AS (Advanced Subsidiary) is taken the first year at 16/17 years and then A2s the next year. So you can now have A levels (AS and A2) in for example Spanish, English and German but also AS´s in Maths and Biology which are really only half an A level. Complicated!