假定英语课上老师要求同桌之间交换修改作文，请你修改你同旧式写的一下作文。文中共有10处语言错误，每句中最多有两处。错误涉及一个单词的增加、删除或修改。
增加：在缺词处加一个漏字符号，并在其下面写出该加的词。
删除：把多余的词作斜线（\）划掉
修改：在错的词下划一横线，并在该词下面写出修改后的词。
注意：1．每处错误及其修改均仅限一词；
2．只允许修改10处，多者（从第11处起）不计分。
Dear Robert,
Thank for your letter of May 12th. How glad I was when I get it. I’d
be very happy to be your pen friends. Now allow me introduce myself to
you. I’m a boy student aging seventeen, study in Senior Three of Hongqi
High School. I’m a monitor of my class. I am about to take National
Matriculation Entrance Examination after twenty days, that is,
between June 7 and 8．You know. I want very much to be a doctor working
for poor peasants that I try to make fully use of every hour
and study far into the night every day.
Best wishes！
Yours truly