短文改错（共10小题 ；每小题1.5分, 满分15分 ）
此题要求改正所给短文的错误。对标有题号的每一行做出判断：如无错误，在该行右边横线上画一个（√）；如有错误（每行只有一个错误），则按下列情况改正：
该行多一个词 ：把多余的词用斜线（\）划掉，在该行右边横线上写出该词，并也用斜线划掉。该行缺一个词：在缺词处加一个漏字符号（∧），在该行右边横线上写出该加的词。该行错一个词：在错的词下划一横线，在该行右边横线上写出改正后的词。注意：原行没有错的不要改正。
Dear Editor,
Recently, my classmates have had a heated discussion about that     
_______
we should have optional courses(选修课) in high schools. Some students were _______
in favor of the optional courses. They say interest is the 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. In addition to, 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 the optional _______
courses. I’d like to take one or two of the optional courses, which, I think,
will certain benefit me a lot.                                     
______