Writing prompt: Sweeping Snow

Student essay:
When I got up, I opened the curtain and found it was snowing. The whole world became white. It was very beautiful. I decided to go outside to take some photos.
It was cold, so I put on my overcoat. When I walked on the street, I took lots of wonderful pictures. Suddenly, I saw a man who walked in front of me fell down.
I went back home immediately. I took a broom and wanted to sweep the snow.
When the person who walked on the street saw I clean the snow. They praised me for my behavior.
Helping others makes me feel happy and I am proud of myself.

Corrected essay:
When I got up, I opened the curtain and found it was snowing. The whole world became white. It was very beautiful. I decided to go outside to take some photos.
It was cold, so I put on my overcoat. When I walked on the street, I took lots of wonderful pictures. Suddenly, I saw a man who was walking in front of me fall down.
I went back home immediately. I took a broom and wanted to sweep the snow. When the people who were walking on the street saw me cleaning the snow, they praised me for my behavior.
Helping others made me feel happy and I was proud of myself.

Error analysis:
error_sentence: Suddenly, I saw a man who walked in front of me fell down.

correct_sentence: Suddenly, I saw a man who was walking in front of me fall down.

error: walked
correction: was walking
error_type: Verb Tense Error
error_severity: 3
error_description: Verb Tense Error: According to the context, the action was ongoing when 〈saw〉 occurred, so the past continuous tense should be used. The original sentence uses the simple past tense 〈walked〉, so it needs to be changed to the past continuous tense 『was walking』 to fit the context.
error_sentence: Suddenly, I saw a man who walked in front of me fell down.

correct_sentence: Suddenly, I saw a man who was walking in front of me fall down.

error: fell
correction: fall
error_type: Nonfinite Verb Form Error
error_severity: 3
error_description: Nonfinite Verb Form Error: According to English grammar rules, the sensory verb 〈saw〉 should be followed by the base form of the verb to indicate the complete process, so 〈fell〉 needs to be changed to 『fall』 to comply with grammar.
error_sentence: I took a broom and wanted to sweep the snow.

correct_sentence: I took a broom and wanted to sweep the snow. When the people who were walking on the street saw me cleaning the snow, they praised me for my behavior.

error: 

error_type: Sentence Structure Error
error_severity: 4
error_description: Sentence Structure Error: According to the context, the sentence structure here is incomplete, lacking necessary subsequent information to maintain contextual coherence. Therefore, the two paragraphs need to be merged into one to conform to the contextual logic.
error_sentence: When the person who walked on the street saw I clean the snow.
correct_sentence: When the people who were walking on the street saw me cleaning the snow, they praised me for my behavior.

error: person who walked
correction: people who were walking
error_type: Verb Tense Error
error_severity: 5
error_description: ① Noun Number Error: According to the context, the noun 〈person〉 needs to be in the plural form 『people』 to match the sentence subject 〈they〉, so 〈person〉 is changed to 『people』 to comply with grammatical rules and context; ② Verb Tense Error: According to the context, this is a time adverbial clause introduced by 〈when〉, and the past continuous tense should be used. The original sentence uses the simple past tense 〈walked〉, so it needs to be changed to the past continuous tense 『were walking』 to fit the context.
error_sentence: When the person who walked on the street saw I clean the snow.
correct_sentence: When the people who were walking on the street saw me cleaning the snow, they praised me for my behavior.

error: I clean
correction: me cleaning
error_type: Nonfinite Verb Form Error
error_severity: 5
error_description: ① Pronoun Error: According to the meaning and English grammar rules, the sensory verb 〈saw〉 needs to be followed by the objective case. Here, to express '我', the objective form 『me』 is needed, so 〈I〉 needs to be changed to 『me』 to comply with grammar; ② Nonfinite Verb Form Error: According to English grammar rules, the sensory verb 〈saw〉 should be followed by the present participle form of the verb to indicate an ongoing action, so 〈clean〉 needs to be changed to 『cleaning』 to comply with grammar.
error_sentence: When the person who walked on the street saw I clean the snow. They praised me for my behavior.

correct_sentence: When the people who were walking on the street saw me cleaning the snow, they praised me for my behavior.

error: . They
correction: , they
error_type: Punctuation Error
error_severity: 2
error_description: Punctuation Error: According to English grammar rules, a comma is needed to connect the time adverbial clause 〈When...snow〉 with the main clause. Therefore, 〈snow. They〉 in the original sentence needs to be changed to 『snow, they』 to comply with grammar.
error_sentence: Helping others makes me feel happy and I am proud of myself.
correct_sentence: Helping others made me feel happy and I was proud of myself.
error: makes
correction: made
error_type: Verb Tense Error
error_severity: 3
error_description: Verb Tense Error: According to the context, the simple past tense should be used here. The original sentence uses the simple present tense 〈makes〉, so it needs to be changed to the past tense 『made』 to fit the context.
error_sentence: Helping others makes me feel happy and I am proud of myself.
correct_sentence: Helping others made me feel happy and I was proud of myself.
error: am
correction: was
error_type: Verb Tense Error
error_severity: 3
error_description: Verb Tense Error: According to the context, the simple past tense should be used here. The original sentence uses the simple present tense 〈am〉, so it needs to be changed to the past tense 『was』 to fit the context.