Dear Cecile and Maarten,
Thank you both for your explanations. I have read the lesson you refer to several times, as well as the relevant links, (and done the kwizes), but I still get a little confused with this issue. I plan to review this subject regularly, as I have found by doing so I eventually achieve an understanding of subjects that at first are not clear to me. I am wondering if maybe the lesson could be expanded someway to include more exercise questions or if it could be broken up into several separate lessons? Perhaps "an/annee" could have its own lesson?
Merci beaucoup !