根据下面资料，回答题
Many years ago, when I was working in a school in Buenos Aires, I was required to teach Macbethto a class of Spanish-speaking schoolboys. I was a bit worried at being given such a task, becauseShakespeare' s language is not always easy, even for the native speaker. The language of Macbeth isparticularly rich and strange to the modem reader. I myself had seen and read the play for the first timeat an early age, and had been carried away by the story. So, I decided to concentrate first on the actionand plot, and as far as possible let the language take care of itself.
I read the play to my students, scene by scene, taking the different parts myself. I did not let mypupils read it aloud for themselves, as I thought they lacked necessary experience and skill to benefitfrom this. At the end of each scene, I saw to it that everybody understood what had happened, and webriefly summarized this in writing. After this, I went through the scene again, explaining those languagepoints that might prevent essential comprehension, and then I read the scene straight through once more.
This was not a very exciting approach. The pupils' participation was largely passive. I was in factdoing most of the work. However, when we had gone through about half of the play in this manner, Idiscovered to my great surprise that the class had taken the book home and finished it for themselves.Through my efforts, they had woken up to the idea that the story was exciting, and wanted to know howit turned out in the end.
We went ahead and finished the play, working more rapidly, and went on to discuss and read partsof the play again, focusing on the characters, plots, themes, etc. Without noticing it, we did a lot ofpractice in oral and written English.
What made the teaching of Macbeth a worrying task?