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：把多余的词用斜线（\）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。
Dear Mr. Black,
I’m Li Hua, an exchange student from China. I had been studying in your
school for a year. I am deep moved by the kindness of people around. What I want
to say first is that the teachers here are very friendly. They do what they can help
me and encourage me to study hard. Whenever asking, they give satisfactory
answers. Beside, my classmates offer me a lot of help, either. We get on well to
each other and I have made quite a few good friend. At home, Walter’s parents take
good care of me, treating to me as if I were their own child.
I’m so grateful to all these people, with their help I have been accustomed to American culture and gained a lot of knowledge.
Best wishes!
Yours,
Li Hua