Writing prompt: Based on the given hints and referring to the picture, write a short essay.
Last Sunday, I went for a picnic in the park with my friends. It started raining in the afternoon. I forgot my umbrella and got wet. I felt cold and had a headache. My friends took me to the hospital. The doctor said I had a fever. He gave me some medicine and told me to go home and rest well.
Writing hints: picnic; rain; umbrella; get wet; hospital; fever; medicine.

Student essay:
On the last Sunday. I and my friends picnic on park. In the afternoon raining I'm way. I feel cold and headache.

Corrected essay:
Last Sunday, my friends and I had a picnic in the park. In the afternoon, it started raining, and I got wet. I felt cold and had a headache.

Error analysis:
error_sentence: On the last Sunday. I and my friends picnic on park.
correct_sentence: Last Sunday, my friends and I had a picnic in the park.
error: On the last Sunday. I and my friends picnic on
correction: Last Sunday, my friends and I had a picnic in the
error_type: Word Redundancy Error
error_severity: 5
error_description: ① Word Redundancy Error: According to English grammar rules, the time phrase “last Sunday” can be placed at the beginning of a compound sentence as a time adverbial meaning “last Sunday” without needing a preposition; therefore, 〈On the last Sunday〉 should be changed to 『Last Sunday』 to comply with English grammar rules; ② Punctuation Error: According to English grammar rules, a comma is needed between the time adverbial and the main clause; therefore, a comma should be added after 『Last Sunday』; ③ Word Order Error: According to English expression conventions, when a first-person and a third-person pronoun serve as coordinate subjects, the third person should precede the first person out of respect; therefore, the word order needs adjustment, changing 〈I and my friends〉 to 『my friends and I』 to conform to English expression habits; ④ Sentence Structure Error: According to the original sentence's meaning, it intends to express “had a picnic”; the original sentence lacks a predicate verb, making the structure incomplete; 『had a』 needs to be added before 〈picnic〉 to form the verb phrase “had a picnic” to match the original meaning and syntactic rules; ⑤ Preposition Error: According to English fixed phrases, the correct expression for “in the park” is “in the park”; the preposition in “on park” is incorrect and needs to be changed to 『in』; ⑥ Determiner Error: Here, the park is used specifically; the definite article 『the』 needs to be added before 〈park〉 to indicate specificity according to English grammar rules.

error_sentence: In the afternoon raining I'm way.
correct_sentence: In the afternoon, it started raining, and I got wet.
error: raining I'm way
correction: , it started raining, and I got wet
error_type: Sentence Structure Error
error_severity: 5
error_description: ① Punctuation Error: According to English syntactic rules, in a complete compound sentence, when a time adverbial is at the beginning, it should be separated from the following main clause by a comma; therefore, a 『,』 needs to be added after 〈afternoon〉 to comply with English syntactic rules; ② Sentence Structure Error: The original phrase “开始下雨” (started raining) lacks a subject and predicate verb; therefore, the pronoun “it” needs to be added as a formal subject, and the past tense “started” of the predicate verb “start” needs to be added to form the subject-verb component 『it started』 to complete the sentence structure; according to the original prompt and context tense, the original 〈I'm way〉 cannot accurately express “I got wet”; 〈I'm way〉 needs to be changed to 『I got wet』 to match the original prompt and context tense; ③ Conjunction Error: According to English syntactic rules, in a compound sentence, the last two clauses containing independent subject-verb structures should be connected by a comma and a coordinating conjunction like 'and'; the original clauses 〈 it started raining〉 and 〈I got wet〉 are the last two clauses with independent subject-verb structures in the compound sentence and their meanings have a close sequential relationship; therefore, 『, and』 needs to be added after 〈raining〉 to comply with English syntactic rules.

error_sentence: I feel cold and headache.
correct_sentence: I felt cold and had a headache.
error: feel
correction: felt
error_type: Verb Tense Error
error_severity: 3
error_description: Verb Tense Error: According to the context, the original tense is simple past tense, so there is a verb tense error here. The base form of the predicate verb 〈feel〉 needs to be changed to the simple past tense 『felt』 to match the context tense.

error_sentence: I feel cold and headache.
correct_sentence: I felt cold and had a headache.
correction: had a
error_type: Verb Choice Error
error_severity: 4
error_description: Verb Choice Error: According to the English fixed phrase, the verb phrase “have a headache” means “headache”. The original sentence lacks the corresponding predicate verb, resulting in an incomplete sentence structure and a sentence structure error. 『had a』 needs to be added before 〈headache〉 to form the verb phrase, completing the verb-object structure in the sentence to clearly express the meaning of “headache” in accordance with the English fixed phrase and the original sentence meaning.