Writing prompt: How Can We Use Cellphones?

Student essay:
Cell phones have become increasingly popular in china these days. wherever you go you can see people using cell phones. many high school students have cell phones.
Cell phones have brought people a lot of benefits, but the most important is that they are convenient. with cell phones in their hands, they can keep in touch with anybody they want. if someone has a heart attack or a traffic accident, a call to emergency hospital or to the police can quickly bring him the help he wants.
However, cell phones can also bring people problems. the most serious problem is that when people are having a meeting or at a concert etc, the ring of the cell phone may interrupt others. so i think people should use cellphones as little as possible.

Corrected essay:
Cell phones have become increasingly popular in China these days. Wherever you go you can see people using cell phones. Many high school students have cell phones.
Cell phones have brought people a lot of benefits, but the most important is that they are convenient. With cell phones in their hands, they can keep in touch with anybody they want. If someone has a heart attack or a traffic accident, a call to an emergency hospital or to the police can quickly bring him the help he wants.
However, cell phones can also bring people problems. The most serious problem is that when people are having a meeting or at a concert, etc., the ring of the cell phone may interrupt others. So I think people should use cell phones as little as possible.

Error analysis:
error_sentence: Cell phones have become increasingly popular in china these days.
correct_sentence: Cell phones have become increasingly popular in China these days.
error: china
correction: China
error_type: Case Error
error_severity: 1
error_description: Case Error: According to English proper noun capitalization rules, the country name 〈china〉, as a specific place name, must have its first letter capitalized, therefore it is changed to 『China』 to comply with grammatical norms.
error_sentence: wherever you go you can see people using cell phones.
correct_sentence: Wherever you go you can see people using cell phones.
error: wherever
correction: Wherever
error_type: Case Error
error_severity: 1
error_description: Case Error: According to English sentence structure rules, the first letter of the sentence-initial word 〈wherever〉 needs to be capitalized, therefore it is changed to 『Wherever』 to ensure correct sentence format.
error_sentence: many high school students have cell phones.

correct_sentence: Many high school students have cell phones.

error: many
correction: Many
error_type: Case Error
error_severity: 1
error_description: Case Error: According to English sentence writing conventions, the first letter of the sentence-initial word 〈many〉 needs to be capitalized, therefore it is changed to 『Many』 to conform to standard English format.
error_sentence: with cell phones in their hands, they can keep in touch with anybody they want.
correct_sentence: With cell phones in their hands, they can keep in touch with anybody they want.
error: with
correction: With
error_type: Case Error
error_severity: 1
error_description: Case Error: According to English grammar rules, the first letter of the sentence-initial word 〈with〉 needs to be capitalized, therefore it is changed to 『With』 to ensure standard sentence structure.
error_sentence: if someone has a heart attack or a traffic accident, a call to emergency hospital or to the police can quickly bring him the help he wants.

correct_sentence: If someone has a heart attack or a traffic accident, a call to an emergency hospital or to the police can quickly bring him the help he wants.

error: if
correction: If
error_type: Case Error
error_severity: 1
error_description: Case Error: According to English grammar requirements, the first letter of the sentence-initial word 〈if〉 needs to be capitalized, therefore it is changed to 『If』 to maintain consistent sentence format.
error_sentence: if someone has a heart attack or a traffic accident, a call to emergency hospital or to the police can quickly bring him the help he wants.

correct_sentence: If someone has a heart attack or a traffic accident, a call to an emergency hospital or to the police can quickly bring him the help he wants.

correction: an
error_type: Determiner Error
error_severity: 2
error_description: Determiner Error: According to English article usage rules, the singular countable noun 〈emergency hospital〉 requires the indefinite article 『an』 before it to indicate a general reference, therefore it is changed to 『an emergency hospital』 to comply with grammatical norms.
error_sentence: the most serious problem is that when people are having a meeting or at a concert etc, the ring of the cell phone may interrupt others.
correct_sentence: The most serious problem is that when people are having a meeting or at a concert, etc., the ring of the cell phone may interrupt others.
error: the
correction: The
error_type: Case Error
error_severity: 1
error_description: Case Error: According to English grammar requirements, the first letter of the sentence-initial word 〈the〉 needs to be capitalized, therefore it is changed to 『The』 to maintain consistent sentence format.
error_sentence: the most serious problem is that when people are having a meeting or at a concert etc, the ring of the cell phone may interrupt others.
correct_sentence: The most serious problem is that when people are having a meeting or at a concert, etc., the ring of the cell phone may interrupt others.
error: etc
correction: , etc.
error_type: Punctuation Error
error_severity: 2
error_description: Punctuation Error: According to English punctuation rules, the Latin abbreviation 〈etc.〉, meaning 'and so on', when used in a sentence, needs a comma before it to separate parallel elements, and the period of the abbreviation itself cannot be omitted, therefore it is changed to 『, etc.』 to ensure correct punctuation.
error_sentence: so i think people should use cellphones as little as possible.
correct_sentence: So I think people should use cell phones as little as possible.
error: so i
correction: So I
error_type: Case Error
error_severity: 2
error_description: ① Case Error: According to English sentence writing conventions, the first letter of the sentence-initial word 〈so〉 needs to be capitalized, therefore it is changed to 『So』; ② Case Error: According to English personal pronoun rules, the first-person singular pronoun 〈I〉 must be capitalized in any position, therefore 〈i〉 is changed to 『I』 to conform to correct spelling.
error_sentence: so i think people should use cellphones as little as possible.
correct_sentence: So I think people should use cell phones as little as possible.
error: cellphones
correction: cell phones
error_type: Space Error
error_severity: 1
error_description: Space Error: According to English compound word writing conventions, 〈cellphones〉 should be separated into two independent words 〈cell phones〉 to express mobile phones, therefore it is changed to 『cell phones』 to conform to standard English expression.