Otto Jespersen,
How to Teach a Foreign Language
“ I once read a pedagogical article by a German schoolmaster, I think it was, who had discovered that the reason why there were so many poor Latin exercises written was that the pupils often had to apply several rules of syntax in one and the same sentence; if the sentences were only so made that each one of them contained but one grammatical phenomenon, it would soon be seen how clever the pupils could be. Yes, how pleasant it would be if life too could be so arranged as to have the difficulties come one at a time. ”
