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 am a boy. I am fourteen years old. I have a brother and a sister. And my parents. We plan to go to beijing this summer holiday. First, we will go to square. It is one of the symbols of China. Then we will go to the palace museum. It's wonderful and beautiful. Last but not least. We must eat beijing duck. It is very delicious.

Corrected essay:
I am a boy. I am fourteen years old. I have a brother, a sister and my parents. We plan to go to Beijing this summer holiday. First, we will go to Tian'anmen Square. It is one of the symbols of China. Then we will go to the Palace Museum. It's wonderful and beautiful. Last but not least, we must eat Beijing Roast Duck. It is very delicious.

Error analysis:
error_sentence: I have a brother and a sister.
correct_sentence: I have a brother, a sister and my parents.
error: and
correction: ,
error_type: Conjunction Error
error_severity: 4
error_description: Conjunction Error: According to English grammar rules, when listing three or more parallel elements, a comma 『, 』 should be used to separate the parallel elements except for the last two; therefore, the original phrase 〈a brother and a sister〉 should be changed to 『a brother, a sister and my parents』 to conform to English grammar.
error_sentence: I have a brother and a sister. And my parents.
correct_sentence: I have a brother, a sister and my parents.
error: . And
correction: and
error_type: Conjunction Error
error_severity: 5
error_description: ① Punctuation Error: According to English grammar rules, 〈And my parents〉 as an independent sentence is structurally incomplete and needs to be merged with the preceding sentence; therefore, the 『.』 in 〈. And〉 should be removed to conform to grammar. ② Conjunction Error: According to English grammar rules, when listing three or more parallel elements, the 『and』 structure should be used between the last two elements; therefore, the original phrase 〈a brother and a sister〉 should be changed to 『a brother, a sister and my parents』 to conform to English grammar.
error_sentence: We plan to go to beijing this summer holiday.
correct_sentence: We plan to go to Beijing this summer holiday.
error: beijing
correction: Beijing
error_type: Case Error
error_severity: 1
error_description: Case Error: According to English writing conventions, the first letter of proper nouns needs to be capitalized; 〈beijing〉 is a proper noun representing the place "Beijing", therefore 〈beijing〉 needs to be changed to 『Beijing』 to conform to conventions.
error_sentence: First, we will go to square.
correct_sentence: First, we will go to Tian'anmen Square.
error: square
correction: Tian'anmen Square
error_type: Noun Error
error_severity: 3
error_description: Noun Error: According to the prompt requirements and given hints, the intended meaning here is "Tian'anmen Square"; in the original sentence, 〈square〉 means "square", which is a noun error; therefore, 〈square〉 needs to be changed to 『Tian'anmen Square』 to meet the prompt requirements.
error_sentence: Then we will go to the palace museum.
correct_sentence: Then we will go to the Palace Museum.
error: palace museum
correction: Palace Museum
error_type: Case Error
error_severity: 1
error_description: Case Error: According to English writing conventions, the first letter of proper nouns needs to be capitalized; 〈palace museum〉 is a proper noun representing "the Palace Museum", therefore 〈palace museum〉 needs to be changed to 『Palace Museum』 to conform to conventions.
error_sentence: Last but not least. We must eat beijing duck.
correct_sentence: Last but not least, we must eat Beijing Roast Duck.
error: . We
correction: , we
error_type: Punctuation Error
error_severity: 2
error_description: Punctuation Error: According to English grammar rules, the transitional phrase 〈Last but not least〉 should be followed by a comma to connect to the main clause, rather than forming an independent sentence; therefore, the original phrase 〈. We〉 needs to be changed to 『, we』 to conform to grammar rules.
error_sentence: We must eat beijing duck.
correct_sentence: Last but not least, we must eat Beijing Roast Duck.
error: beijing duck
correction: Beijing Roast Duck
error_type: Noun Error
error_severity: 3
error_description: Noun Error: According to the sentence meaning and given hints, the intended meaning here is "Beijing Roast Duck"; in the original sentence, 〈beijing duck〉 means "Beijing duck", which is a noun error; therefore, 〈beijing duck〉 needs to be changed to 『Beijing Roast Duck』 to meet the prompt requirements.