短文改错 Recently, my classmates have had a hea ted discussion about if we should have optional courses (选修课) in high schools. Some students were  in favor of optional courses. They say interest is best teacher and  our spare time will be colorful and meaningful. Students can not only  enlarge their knowledges but also improve their abilities.  However, others are against the idea, said that optional courses will take up too much time as well as energy. Besides, some optional courses have something to do with the College Entrance Examination. They are afraid they'll fall behind their classmates if they will take optional courses. I'd like to take one or two  of the optional courses, which, I think, will certain benefit me  lot. _____________________________________________________________________________