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 journey. It gives a broad overview of the beginning of the learning process without needing prior context. It does not use any definite articles or pronouns that refer to previous ideas. Why other lines are not chosen? Paragraph 2 starts with "Throughout this period," which needs context from earlier sentences. Paragraph 3 starts with "The transition," which also needs prior information. Paragraph 4 starts with "After months of practice," which assumes knowledge of earlier events.

Concluding sentence: Why this is the last line? This paragraph is the last sentence because it wraps up the journey. It shows the final achievement after all the practice and challenges. It gives a sense of closure to the story.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): The second paragraph connects to the first because it continues the idea of learning. The first paragraph talks about starting lessons, and the second shows how practice became important during this time. This shows a logical order of learning.
• Pair 2 (Paragraph 2 → Paragraph 3): The third paragraph follows the second because it describes a specific challenge that comes after regular practice. It shows a logical order where practice leads to new skills, like playing with both hands.
• Pair 3 (Paragraph 3 → Paragraph 4): The fourth paragraph connects to the third because it shows the result of the hard work. After facing challenges, the speaker can now play full songs. This shows a clear progression from challenge to success.