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; your pen friend. My family has three people; My parents and me. My father is a worker, and my mother is a doctor. They both are busy. I have a plan to Beijing in the summer hoilday. Firstly, I want to go to Tian'anmen Square best. It's so famous. Next, I plan to visit the Palace Museum. Because I think it records the development of history. At last, I'll eat delicious food that is Beijing Roast Duck. I hear many people recommend it.

Corrected essay:
I'm Lin Chen, your pen friend. My family has three people. They are my parents and me. My father is a worker, and my mother is a doctor. They are both busy. I have a plan for going to Beijing in the summer holiday. Firstly, I want to go to Tian'anmen Square the most. It's so famous. Next, I plan to visit the Palace Museum because I think it records the development of history. At last, I'll eat delicious food that is Beijing Roast Duck. I hear many people recommend it.

Error analysis:
error_sentence: I'm Lin Chen; your pen friend.
correct_sentence: I'm Lin Chen, your pen friend.
error: ;
correction: ,
error_type: Punctuation Error
error_severity: 2
error_description: ① Punctuation Error: According to English punctuation rules, a semicolon 〈;〉 connects two independent clauses, but 〈your pen friend〉 here is an appositive, not an independent clause; a comma 『,』 should be used to connect the main clause and the appositive. The original sentence's use of 〈;〉 violates grammatical rules and is a punctuation error; 〈;〉 needs to be changed to 『,』 to maintain sentence coherence and conform to common English writing conventions.

error_sentence: My family has three people; My parents and me.
correct_sentence: My family has three people. They are my parents and me.
error: ; My
correction: . They are my
error_type: Sentence Structure Error
error_severity: 5
error_description: ① Punctuation Error: According to English punctuation rules, a semicolon 〈;〉 cannot connect the main clause 〈My family has three people〉 and the independent explanatory phrase 〈My parents and me〉; a period 〈.〉 should be used to separate them into two independent sentences, meaning it should be changed to 『My family has three people.』; ② Sentence Structure Error: According to English grammar, the second sentence lacks a subject-verb structure, cannot form a complete and accurate sentence, and cannot clearly refer to the preceding 〈three people〉; 『They are』 needs to be added before the second sentence as the subject and verb to clarify the reference.

error_sentence: They both are busy.
correct_sentence: They are both busy.
error: both are
correction: are both
error_type: Word Order Error
error_severity: 4
error_description: ① Word Order Error: According to English grammar rules regarding adverb placement, the adverb 〈both〉 when used after a linking verb, should be placed after the linking verb 〈are〉. The word order 〈both are〉 in the original sentence does not conform to this rule and is a word order error. 〈both are〉 needs to be adjusted to 『are both』 to make the sentence conform to English expression habits and grammatical rules.

error_sentence: I have a plan to Beijing in the summer hoilday.
correct_sentence: I have a plan for going to Beijing in the summer holiday.
correction: for going
error_type: Nonfinite Verb Form Error
error_severity: 5
error_description: ① Preposition Error: According to English grammar rules, the preposition 〈to〉 cannot directly follow a location to express the purpose of a plan; when expressing a plan, the preposition 〈for〉 is usually followed by a gerund form to indicate purpose. The original sentence's use of 〈to〉 does not conform to the rule and is a preposition error; 〈plan to〉 should be changed to 『plan for』 to comply with grammatical rules; ② Nonfinite Verb Form Error: The preposition 〈for〉 needs to be followed by a gerund form to express the content of the plan; the original phrase 〈plan to Beijing〉 lacks a gerund form, which is a nonfinite verb form error. The gerund 『going』 should be added after 『for』 to indicate the purpose of the plan, changing 〈plan to Beijing〉 to 『plan for going to Beijing』 to make the sentence conform to grammatical rules.

error_sentence: I have a plan to Beijing in the summer hoilday.
correct_sentence: I have a plan for going to Beijing in the summer holiday.
error: hoilday
correction: holiday
error_type: Spelling Error
error_severity: 2
error_description: ① Spelling Error: Based on the sentence's meaning, the intended word is "holiday"; therefore, 〈hoilday〉 is a misspelling of 『holiday』 and needs to be corrected to 『holiday』 for the sentence to make sense.

error_sentence: Firstly, I want to go to Tian'anmen Square best.
correct_sentence: Firstly, I want to go to Tian'anmen Square the most.
error: best
correction: the most
error_type: Adverb Error
error_severity: 3
error_description: ① Adverb Error: According to English grammar rules, 〈best〉 is a superlative adjective and cannot modify the verb phrase 〈want to go〉. To modify a verb phrase to indicate degree, a superlative adverb is needed. The use of 〈best〉 to modify 〈want to go〉 in the original sentence violates grammatical rules and is an adverb error; 〈best〉 should be changed to 『the most』 to conform to correct expression and grammatical standards.

error_sentence: Next, I plan to visit the Palace Museum. Because I think it records the development of history.
correct_sentence: Next, I plan to visit the Palace Museum because I think it records the development of history.
error: . Because
correction: because
error_type: Punctuation Error
error_severity: 2
error_description: ① Punctuation Error: According to English grammar rules, an adverbial clause of reason introduced by the subordinating conjunction 〈because〉 cannot stand as an independent sentence. In the original sentence, 〈. Because〉 incorrectly makes the clause an independent sentence; the period needs to be deleted and 〈. Because〉 changed to 『 because』, merging it with the preceding sentence to avoid punctuation errors and ensure a complete sentence structure.