Writing prompt: Written Expression. Assume you are Lin Chen and have just made a new pen pal named Ted. Please write a letter to him describing your personal background, family situation, and your plan to visit Beijing over the summer. Writing hints: Tian'anmen Square, the Palace Museum, Beijing Roast Duck.
Dear Ted,
________
Welcome to China. Have a good day!
Yours,
Lin Chen

Student essay:
I'm Lin Chen. I am very happy to be pen-friend with you. There are three people in my family, my father, my mother and I. I love my parents very much, and they love me too. I plan to go go Beijing this summer holiday. First, I will take a visit to Tian'anmen Square. There I will watch the raising of the national flag. Next, I will visit the Palace Museum for one day because I like history very much. At last, I will go to eat Beijing Roast Duck. Yours Lin Chen

Corrected essay:
I'm Lin Chen. I am very happy to be pen friends with you. There are three people in my family: my father, my mother and me. I love my parents very much, and they love me too. I plan to go to Beijing this summer holiday. First, I will take a visit to Tian'anmen Square. There I will watch the raising of the national flag. Next, I will visit the Palace Museum for one day because I like history very much. At last, I will go to eat Beijing Roast Duck.
Yours，
Lin Chen

Error analysis:
error_sentence: I am very happy to be pen-friend with you.
correct_sentence: I am very happy to be pen friends with you.
error: -friend
correction: friends
error_type: Noun Number Error
error_severity: 2
error_description: Noun Number Error: When expressing a pen pal relationship, 〈pen-friend〉 should be in the plural form 『pen friends』, as both parties are pen pals to each other; the singular form can only refer to a one-way relationship, which does not fit the actual meaning, therefore 〈-friend〉 is changed to 『friends』.

error_sentence: There are three people in my family, my father, my mother and I. I love my parents very much, and they love me too.
correct_sentence: There are three people in my family: my father, my mother and me.
error: ,
correction: :
error_type: Punctuation Error
error_severity: 1
error_description: Punctuation Error: According to English grammar rules, a colon is used to introduce explanatory content; in the original sentence, when listing family members, using 〈,〉 for connection is not clear enough, a 『:』 should be used to indicate the listing relationship, therefore 〈,〉 is changed to 『:』.

error_sentence: There are three people in my family, my father, my mother and I. I love my parents very much, and they love me too.
correct_sentence: There are three people in my family: my father, my mother and me.
error: I.
correction: me.
error_type: Pronoun Error
error_severity: 2
error_description: Pronoun Error: When 〈and〉 connects parallel objects, the pronoun needs to be in the objective case; 〈I〉 is in the nominative case, therefore 〈I〉 is changed to the objective case 『me』 to comply with grammatical rules.

error_sentence: I plan to go go Beijing this summer holiday.
correct_sentence: I plan to go to Beijing this summer holiday.
error: go
correction: to
error_type: Word Redundancy Error
error_severity: 3
error_description: Word Redundancy Error: In the original sentence 〈I plan to go go Beijing〉, the verb 〈go〉 is used repeatedly, leading to semantic redundancy; the correct structure is 『go to Beijing』, therefore the redundant verb 〈go〉 is deleted and the preposition 『to』 is added to conform to phrasal verb collocation.

error_sentence: Yours Lin Chen
correct_sentence: At last, I will go to eat Beijing Roast Duck.
 Yours，
Lin Chen
error: Yours
correction: 
Yours，

error_type: Format Error
error_severity: 3
error_description: Format Error: The closing of an English letter needs to be written with line breaks. The original sentence did not use line breaks; it should be changed to 『Yours，Lin Chen』 to comply with standard format specifications.