1. "I think it is impossible to find the perfect book; each one has good and bad features."
I agree. I think it's impossible to find the perfect book. This is because every teacher and every class, every group are different, we can find better activities that are funtional in a group, but is the most boring activity for another one... It depends... some books had a higest level for the students, so it´s so difficult to say that one of the books is the best... However, I can´t chose my own book; even if a like one than other... so, I improve my work with copies, I have materials of my own and I complement with the book...