Writing prompt: A Brief Introduction to the UK

Student essay:
Britain, the full name of The United Kingdom of Great Britain and Northern Ireland. Britain is made up of England, Northern Ireland, Scotland and Welsh.
The United Kingdom merged with Ireland in 1801 and the United Kingdom's official became The United Kingdom of Great Britain and Northern Ireland.
Britain in the early 19th century reached its peak, at the time, accounting for a quarter of the world's population; territorial accounted for a quarter of the total land area in the world. Britain is the first industrialized country in the world. It was known as the Empire on which the suns never sat.
As time goes by, Britain is still a big country in the world.

Corrected essay:
Britain, the full name of The United Kingdom of Great Britain and Northern Ireland, is made up of England, Northern Ireland, Scotland and Wales.
The United Kingdom merged with Ireland in 1801, and its official name became The United Kingdom of Great Britain and Northern Ireland.
Britain in the early 19th century reached its peak, at the time accounting for a quarter of the world's population and a quarter of the total land area in the world. Britain is the first industrialized country in the world. It was known as the Empire on which the sun never set.
As time goes by, Britain is still a major country in the world.

Error analysis:
error_sentence: Britain, the full name of The United Kingdom of Great Britain and Northern Ireland. Britain is made up of England, Northern Ireland, Scotland and Welsh.

correct_sentence: Britain, the full name of The United Kingdom of Great Britain and Northern Ireland, is made up of England, Northern Ireland, Scotland and Wales.

error: . Britain
correction: ,
error_type: Sentence Structure Error
error_severity: 4
error_description: ① Punctuation Error: According to English appositive structure rules, the independent clauses 〈Britain...Northern Ireland〉 and 〈Britain is made up...〉 should not be separated by a period; a comma is needed to connect them and form an appositive structure, creating the standard expression 『Britain, the full name...』; ② Sentence Structure Error: According to English sentence completeness principles, the original sentence has a run-on issue; the repeated subject Britain is deleted and the sentence is restructured into the complete appositive structure 『Britain, the full name of The United Kingdom of Great Britain and Northern Ireland, is made up of...』.

error_sentence: Britain is made up of England, Northern Ireland, Scotland and Welsh.

correct_sentence: Britain, the full name of The United Kingdom of Great Britain and Northern Ireland, is made up of England, Northern Ireland, Scotland and Wales.

error: Welsh
correction: Wales
error_type: PoS Confusion Error
error_severity: 3
error_description: PoS Confusion Error: According to English country name expression norms, 〈Welsh〉 is an adjective form; here, a proper noun for the region of Wales is needed, so it is changed to 『Wales』 to accurately refer to the country name.

error_sentence: The United Kingdom merged with Ireland in 1801 and the United Kingdom's official became The United Kingdom of Great Britain and Northern Ireland.

correct_sentence: The United Kingdom merged with Ireland in 1801, and its official name became The United Kingdom of Great Britain and Northern Ireland.

error: and the United Kingdom's official
correction: , and its official name
error_type: Conjunction Error
error_severity: 4
error_description: ① Punctuation Error: According to English parallel structure punctuation rules, a comma plus the conjunction 〈and〉 is needed to connect three parallel clauses, thus adding punctuation to form the standard expression 『England, Wales, and Scotland』; ② Pronoun Error: According to English pronoun agreement principles, since "the United Kingdom" has already been mentioned, to avoid repetition, the possessive pronoun 『its』 is used to replace 『the United Kingdom's』, forming the more concise 『its official name』; ③ Noun Error: According to English noun collocation rules, 〈official〉 as an adjective needs to be paired with a head noun, so it is supplemented as 『official name』 to fully express the concept of "official name".

error_sentence: Britain in the early 19th century reached its peak, at the time, accounting for a quarter of the world's population; territorial accounted for a quarter of the total land area in the world.
correct_sentence: Britain in the early 19th century reached its peak, at the time accounting for a quarter of the world's population and a quarter of the total land area in the world.
error: ,
error_type: Punctuation Error
error_severity: 2
error_description: Punctuation Error: According to English punctuation rules for modifiers, since the modifying phrase 〈at the time〉 is closely related to the main clause, the unnecessary comma after it is deleted to maintain sentence fluency.

error_sentence: Britain in the early 19th century reached its peak, at the time, accounting for a quarter of the world's population; territorial accounted for a quarter of the total land area in the world.
correct_sentence: Britain in the early 19th century reached its peak, at the time accounting for a quarter of the world's population and a quarter of the total land area in the world.
error: ; territorial accounted for
correction: and
error_type: Word Redundancy Error
error_severity: 4
error_description: ① Conjunction Error: According to English rules for connecting parallel elements, the semicolon should be changed to the conjunction 『and』 to connect parallel adjectives, forming the standard structure 『accounting for a quarter of the world's population and a quarter of 』; ② Word Redundancy Error: According to English principles of conciseness, 〈territorial accounted〉 is semantically redundant and is simplified to 『a quarter』 to clearly express the meaning of "one quarter".

error_sentence: It was known as the Empire on which the suns never sat.

correct_sentence: It was known as the Empire on which the sun never set.

error: suns never sat
correction: sun never set
error_type: Noun Number Error
error_severity: 4
error_description: ① Noun Number Error: According to English fixed expression norms, the incorrect plural form 〈the suns〉 is changed to the singular 『the sun』, conforming to the standard expression for "the Empire on which the sun never sets"; ② Spelling Error: According to English idiomatic expression norms, the incorrect past tense 〈sat〉 is changed to the correct past tense 『set』, forming the standard expression 『the sun never set』, to conform to the historical expression convention of "the Empire on which the sun never sets".

error_sentence: As time goes by, Britain is still a big country in the world.
correct_sentence: As time goes by, Britain is still a major country in the world.
error: big
correction: major
error_type: Adjective Error
error_severity: 2
error_description: Adjective Error: According to English formal context vocabulary norms, 〈big〉 is imprecise in meaning and is changed to the more formal 『major』 to appropriately describe Britain's status as a "major country".