A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first sentence because it introduces the main topic of the text, which is the author's journey into urban sketching. It sets the scene and gives a clear overview of what the text will be about. This follows the rule of Topic Sentence. Why other lines are not chosen? The other paragraphs are not chosen because they do not stand alone as the first sentence. For example, Paragraph 2 starts with 'To enhance my skills,' which shows it is not independent. Paragraph 3 starts with 'Engaging with the local sketching community,' which also needs context. Paragraph 4 starts with 'As I shared my sketches online,' which refers back to previous ideas. Paragraph 5 starts with 'Mastery of urban sketching,' which is not a general statement and assumes prior knowledge.

Concluding sentence: Why this is the last line? This paragraph is the last sentence because it wraps up the main ideas of the text. It gives a final thought about what the author learned, which is a summary style. It reflects on the overall theme of the journey into urban sketching.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects with Paragraph 1 because it continues the idea of the author's journey. The phrase 'To enhance my skills' shows a logical order, as it explains what the author did next after starting their journey.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects with Paragraph 2 because it shows the next step in the author's learning process. The phrase 'Engaging with the local sketching community' shows a logical order, as it explains how the author further improved their skills.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects with Paragraph 3 because it shows the result of the author's engagement with the community. The phrase 'As I shared my sketches online' indicates a logical order, as it explains what happened after attending workshops.
• Pair 4 (Paragraph 4 → Paragraph 5): Paragraph 5 connects with Paragraph 4 because it summarizes the author's learning experience. The phrase 'Mastery of urban sketching' provides a broader view of what the author learned, showing a logical progression from personal experiences to general insights.