Writing prompt: A Trip to Mount Yunmen

Student essay:
Last week I went to Mount Yunmen. When I arrived there,it was raining. We have no umbrella,so we had to buy a big umbrella to take shelter from rain.
Mount Yunmen is in Qingzhou of Shandong Province. It's 421 metres high.Standing at the top of the Mount and looked down the scenery.The most famous is a word"life". It's about 7.5 metres high and 3.7 metres wide.
The air is very fresh there. There are many kinds of trees and lots of birds. I had a picnic with my parents and we took photos for the scenery.
I remained by the Mount for about half three hours,and had a great time. I felt very very happy,and I also made some friends there. I hope to go there once again.

Corrected essay:
Last week I went to Mount Yunmen. When I arrived there, it was raining. We had no umbrella, so we had to buy a big umbrella to take shelter from the rain.
Mount Yunmen is in Qingzhou of Shandong Province. It's 421 metres high. Standing at the top of the Mount and looking down at the scenery was breathtaking. The most famous feature is the word "life". It's about 7.5 metres high and 3.7 metres wide.
The air is very fresh there. There are many kinds of trees and lots of birds. I had a picnic with my parents and we took photos of the scenery.
I remained by the mountain for about one and a half hours, and had a great time. I felt very, very happy, and I also made some friends there. I hope to go there once again.

Error analysis:
error_sentence: We have no umbrella,so we had to buy a big umbrella to take shelter from rain.

correct_sentence: We had no umbrella, so we had to buy a big umbrella to take shelter from the rain.

error: have
correction: had
error_type: Verb Tense Error
error_severity: 3
error_description: Verb Tense Error: According to English grammar rules, when describing the same situation or a series of events, tense consistency should be maintained. In this sentence, the tenses of the two parts should be consistent; based on 〈had to buy〉, it is known that the past tense should be used here, so 〈have〉 is changed to 『had』 to unify the tense.
error_sentence: We have no umbrella,so we had to buy a big umbrella to take shelter from rain.

correct_sentence: We had no umbrella, so we had to buy a big umbrella to take shelter from the rain.

correction: the
error_type: Determiner Error
error_severity: 2
error_description: Determiner Error: In this context, 〈rain〉 refers to a specific rainfall, so the definite article 『the』 is needed to clearly refer to this rain; therefore, 『the』 is added before 〈rain〉.
error_sentence: Standing at the top of the Mount and looked down the scenery.
correct_sentence: Standing at the top of the Mount and looking down at the scenery was breathtaking.
error: looked down
correction: looking down at
error_type: Nonfinite Verb Form Error
error_severity: 4
error_description: ① Nonfinite Verb Form Error: According to English grammar rules, parallel structures need to maintain consistent nonfinite verb forms; the verb 〈looked〉 should be changed to the present participle 『looking』 to be consistent with the preceding nonfinite verb 〈Standing〉; ② Preposition Error: After 〈look down〉, the preposition 『at』 needs to be added to indicate 'looking at...', so 『at』 is added after 〈look down〉 to introduce the specific object 〈scenery〉.
error_sentence: Standing at the top of the Mount and looked down the scenery.
correct_sentence: Standing at the top of the Mount and looking down at the scenery was breathtaking.
correction: was breathtaking
error_type: Sentence Structure Error
error_severity: 3
error_description: Sentence Structure Error: Since this is a compound subject formed by 'Standing' and 'looking', we need a predicate verb to describe the characteristic or state of the entire subject; therefore, 『was breathtaking』 is added after 〈scenery〉 as the predicate part to make the sentence structure complete and clear.
error_sentence: The most famous is a word"life".
correct_sentence: The most famous feature is the word "life".
error: is a word"life
correction: feature is the word "life
error_type: Noun Error
error_severity: 3
error_description: ① Noun Error: In the original sentence, 〈The most famous〉 lacks a clear noun to specify what is 'the most famous'; considering the sentence's meaning, 『feature』 should be added after 〈famous〉 to express the content more accurately; ② Determiner Error: To make the sentence clear, the definite article 『the』 should be used to refer to the specific word 〈life〉, so 〈a〉 is changed to 『the』.
error_sentence: I had a picnic with my parents and we took photos for the scenery.

correct_sentence: I had a picnic with my parents and we took photos of the scenery.

error: for
correction: of
error_type: Preposition Error
error_severity: 2
error_description: Preposition Error: According to English collocations, we usually say 'take photos of something' to describe photographing an object or scene, so 〈for〉 is changed to 『of』.
error_sentence: I remained by the Mount for about half three hours,and had a great time.
correct_sentence: I remained by the mountain for about one and a half hours, and had a great time.
error: Mount
correction: mountain
error_type: Noun Error
error_severity: 3
error_description: Noun Error: 〈Mount〉 is a specific name for a mountain, usually used for large mountains (e.g., 'Mount Everest'). For ordinary mountains, the word 『mountain』 should be used, so 〈Mount〉 is changed to 『mountain』.
error_sentence: I remained by the Mount for about half three hours,and had a great time.
correct_sentence: I remained by the mountain for about one and a half hours, and had a great time.
error: half three
correction: one and a half
error_type: Number Error
error_severity: 2
error_description: Number Error: According to English grammar rules, when we express 'half an hour', 'half an hour' or 'one and a half hours' are usually used to express it; therefore, 〈half three〉 is changed to 『one and a half』 to correctly describe the length of time.
error_sentence: I felt very very happy,and I also made some friends there.
correct_sentence: I felt very, very happy, and I also made some friends there.
correction: ,
error_type: Punctuation Error
error_severity: 2
error_description: Punctuation Error: According to English writing conventions, when two identical adverbs are used in parallel, they usually need to be separated by a comma; therefore, a comma 『,』 is added after the first 〈very〉 to improve readability and conform to English writing conventions.