Writing prompt: The weekend is coming. Classmates, what are you planning to do? Using the given vocabulary and sentence patterns, and referring to the picture, write a short essay of about 60 words about your plans for the weekend.
Writing hints: be going to; do cleaning; visit grandparents; have a good time

Student essay:
I'm going to do homework in the weekend. Saturday, It is do cleaning the home. Sunday morning. We visit my grandparents. In night. I will fly a kite. This weekend is have a good time.

Corrected essay:
I'm going to do homework on the weekend. On Saturday, I will clean the house. On Sunday morning, we will visit my grandparents. At night, I will fly a kite. This weekend, I am going to have a good time.

Error analysis:
error_sentence: I'm going to do homework in the weekend.
correct_sentence: I'm going to do homework on the weekend.
error: in
correction: on
error_type: Preposition Error
error_severity: 2
error_description: Preposition Error: According to English fixed expressions, 'on the weekend' is typically used to mean '在周末', not 〈in the weekend〉.
error_sentence: I'm going to do homework in the weekend. Saturday, It is do cleaning the home.
correct_sentence: On Saturday, I will clean the house.
correction: On
error_type: Preposition Error
error_severity: 2
error_description: Preposition Error: 〈Saturday〉 cannot function alone as a time adverbial in the sentence; it requires the preposition 『On』 before it. Therefore, 『On』 is added to complete the adverbial phrase structure and comply with English grammar rules.
error_sentence: Saturday, It is do cleaning the home.
correct_sentence: On Saturday, I will clean the house. On Sunday morning, we will visit my grandparents.
error: It is do cleaning the home.
correction: I will clean the house. On
error_type: Sentence Structure Error
error_severity: 4
error_description: ① Sentence Structure Error: An English sentence can only have one main verb. The original sentence 〈It is do cleaning〉 has a double verb structure and lacks a logical subject. Therefore, the subject 『I』 is added, and following the prompt's requirement for future tense, the structure is changed to the clear subject-verb form 『I will clean』.; ② Noun Error: The common phrase for '清洁房子' is 'clean the house'. 〈home〉 is an uncountable noun and does not fit the intended meaning here; the specific noun 『house』 should be used.; ③ Preposition Error: 〈Sunday morning〉 cannot function alone as a time adverbial; it requires the preposition 『On』 before it. Therefore, 『On』 is added to complete the time adverbial structure and comply with English grammar rules.
error_sentence: Sunday morning. We visit my grandparents.
correct_sentence: On Sunday morning, we will visit my grandparents.
error: . We
correction: , we will
error_type: Verb Tense Error
error_severity: 3
error_description: ① Punctuation Error: 〈Sunday morning〉 acts as a time adverbial modifying the main clause 〈We visit...〉; they should not be separated by a period but connected with a comma. Therefore, the period 〈.〉 is incorrectly used and should be changed to a comma 『,』.; ② Case Error: Because there is a preceding time adverbial phrase, 〈We visit my grandparents〉 is not a standalone sentence, so 〈We〉 should not be capitalized and needs to be changed to lowercase 『we』.; ③ Verb Tense Error: 〈We visit my grandparents〉 is in the simple present tense. According to the prompt's requirement, it should be changed to the simple future tense, hence corrected to 『we will』.
error_sentence: In night.
correct_sentence: At night, I will fly a kite.
error: In night.
correction: At night,
error_type: Preposition Error
error_severity: 3
error_description: ① Preposition Error: In English, 『At night』 is a fixed expression meaning '在晚上'; there is no such expression as 〈In night〉. Therefore, 〈In night〉 should be changed to 『At night』.; ② Punctuation Error: 『At night』 is a time adverbial and should be separated from the following main clause by a comma 『,』, not a period.
error_sentence: This weekend is have a good time.
correct_sentence: This weekend, I am going to have a good time.
error: is
correction: , I am going to
error_type: Sentence Structure Error
error_severity: 4
error_description: ① Punctuation Error: The preceding adverbial phrase 〈This weekend〉 should be separated from the following sentence 『I am going to have a good time』 by a comma for structural clarity. Therefore, a comma 『,』 is added after 〈This weekend〉.; ② Sentence Structure Error: The sentence 〈This weekend is have a good time〉 is a run-on sentence with a confused structure, containing two verbs 〈is〉 and 〈have〉, which violates grammatical rules. The subject 『I』 needs to be added, and considering the overall future tense context, it should be changed to 『I am going to have a good time』 to express the complete intended action.