A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first line because it introduces the main idea of the text. It tells us about the decision to learn piano, which is the main topic. It does not refer to any previous information. Why other lines are not chosen? Paragraph 2 starts with "Initially," which shows it is not independent. Paragraph 3 starts with "One day," but it is not the main topic. Paragraph 4 uses "After several months," which also shows it is not independent.

Concluding sentence: Why this is the last line? This paragraph is the last line because it summarizes the results of the journey. It shows the improvements made after the efforts, which wraps up the main idea.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects with Paragraph 1 because it explains the feelings after starting to learn piano. It shows the logical order of thoughts.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects with Paragraph 2 because it shows what the writer did to overcome the overwhelming feelings. It is a logical order of actions.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects with Paragraph 3 because it shows the results of setting goals. It follows the logical order of cause and effect.