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:
I go on a picnic today, but it's rainy. And I'm not umbrella. So I get wet. Then I'm fever.

Corrected essay:
I went on a picnic last Sunday, but it was rainy. And I didn't have an umbrella. So I got wet. Then I had a fever.

Error analysis:
error_sentence: I go on a picnic today, but it's rainy.
correct_sentence: I went on a picnic last Sunday, but it was rainy.
error: go
correction: went
error_type: Verb Tense Error
error_severity: 3
error_description: Verb Tense Error: According to the prompt, 'Last Sunday' describes a past event, so the simple past tense should be used; the original sentence uses the simple present tense 〈go〉, so it needs to be changed to the simple past tense 『went』 to fit the context.
error_sentence: I go on a picnic today, but it's rainy.
correct_sentence: I went on a picnic last Sunday, but it was rainy.
error: today
correction: last Sunday
error_type: Noun Error
error_severity: 3
error_description: Noun Error: According to the prompt, the time is 'Last Sunday'; the original sentence uses 〈today〉 meaning 'today', which is a noun error, so 〈today〉 needs to be changed to 『last Sunday』 to meet the prompt's requirement.
error_sentence: I go on a picnic today, but it's rainy.
correct_sentence: I went on a picnic last Sunday, but it was rainy.
error: 's
correction: was
error_type: Verb Tense Error
error_severity: 3
error_description: Verb Tense Error: According to the prompt, 'Last Sunday' describes a past event, so the simple past tense should be used; the original sentence uses the simple present tense 〈's〉, so it needs to be changed to the simple past tense 『was』 to fit the context.
error_sentence: And I'm not umbrella.
correct_sentence: And I didn't have an umbrella.
error: 'm not
correction: didn't have an
error_type: Verb Choice Error
error_severity: 5
error_description: ① Verb Choice Error: According to English grammar rules and usage, the be-verb alone indicates 'is/existence'; the original phrase 〈'm not umbrella〉 is grammatically incorrect and needs to be changed to 『didn't have』 to conform to English grammar and context; ② Determiner Error: According to English grammar rules, a singular countable noun must be preceded by an indefinite article; the original sentence lacks the necessary determiner 『an』 before 〈umbrella〉, so the phrase is corrected to 『have an umbrella』 to comply with English grammar rules.
error_sentence: So I get wet.
correct_sentence: So I got wet.
error: get
correction: got
error_type: Verb Tense Error
error_severity: 3
error_description: Verb Tense Error: According to the prompt, 'Last Sunday' describes a past event, so the simple past tense should be used; the original sentence uses the simple present tense 〈get〉, so it needs to be changed to the simple past tense 『got』 to fit the context.
error_sentence: Then I'm fever.
correct_sentence: Then I had a fever.
error: 'm
correction: had a
error_type: Verb Choice Error
error_severity: 4
error_description: ① Verb Choice Error: According to English grammar rules and the prompt, the be-verb alone indicates 'is/existence'; the original word 〈'm〉 does not meet the prompt's requirement and needs to be replaced with 『had』 to conform to English grammar and the prompt; ② Determiner Error: According to English grammar rules, a singular countable noun must be preceded by an indefinite article; the original sentence lacks the necessary determiner 『a』 before 〈fever〉, therefore, the phrase is corrected to 『 had a fever』 to comply with English grammar rules.