A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first sentence because it introduces the main topic of classical music. It gives a broad overview of what classical music is about without needing any prior context. It sets the stage for the discussion that follows. Why other lines are not chosen? The other paragraphs are not chosen as the first sentence because they do not stand alone. For example, 'Moreover, many classical pieces...' starts with a connector, which means it needs previous information. 'It often requires a high degree...' is a specific statement and does not introduce the topic. 'Nevertheless, this genre may not appeal...' also starts with a connector and refers back to previous ideas.

Concluding sentence: Why this is the last line? This paragraph is the last sentence because it wraps up the discussion about classical music. It gives a final thought about how not everyone likes this genre, which reflects the overall theme of the text.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects with Paragraph 1 because it logically follows the introduction of classical music. The topic of skill and training is a natural next step after discussing the history of classical music.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects with Paragraph 2 because it adds more information about classical music. The word 'Moreover' shows that this paragraph gives additional details about the pieces of classical music.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects with Paragraph 3 because it presents a contrast. The word 'Nevertheless' shows that while classical music is celebrated, it may not be liked by everyone.