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 initial interest in chess. It sets the stage for the following paragraphs without needing prior context. It uses an introductory nature to explain how the interest began. Why other lines are not chosen? The other paragraphs are not chosen because they do not stand alone. For example, Paragraph 2 starts with 'Joining,' which is a verb and needs context. Paragraph 3 starts with 'The more I played,' which refers back to playing chess. Paragraph 4 starts with 'My first victory,' which assumes prior knowledge of the author's journey. Paragraph 5 starts with 'Mastery in chess,' which is a specific topic and does not introduce the text.

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 summarizes the overall theme of mastery in chess, which is the final thought the author wants to leave with the reader.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects with Paragraph 1 because it follows the author's journey. The first paragraph talks about the initial interest, and the second shows how that interest grew by joining a club. This is a logical order of events.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects with Paragraph 2 because it shows the result of joining the club. The author played more chess and became fascinated. This shows a cause and effect relationship.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects with Paragraph 3 because it shows the outcome of the author's fascination. The victory in the tournament is a result of the author's increased study and practice. This follows a logical order.
• Pair 4 (Paragraph 4 → Paragraph 5): Paragraph 5 connects with Paragraph 4 because it concludes the author's journey. The victory leads to a deeper understanding of chess, which is the main idea in the last paragraph. This shows a broader to specific strategy.