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. It gives a broad overview of calligraphy in Chinese culture. It does not use any pronouns or definite articles that need prior context. Why other lines are not chosen? Paragraph 2 starts with 'It', which is a pronoun and needs context. Paragraph 3 starts with 'The', which is a definite article and assumes prior knowledge. Paragraph 4 starts with 'Therefore', which is a connector and shows it is not independent.

Concluding sentence: Why this is the last line? This paragraph is the last sentence because it wraps up the main ideas. It summarizes the importance of calligraphy by stating that it conveys deeper ideas, which connects back to the previous paragraphs.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects to Paragraph 1 because it gives more details about calligraphy. It explains how calligraphy is done, which supports the idea that it is a high form of art.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects to Paragraph 2 because it continues to explain calligraphy. It talks about the style and meaning of the characters, which follows logically from how calligraphy is created.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects to Paragraph 3 because it expands on the meaning of calligraphy. It shows that calligraphy is more than just writing; it has deeper ideas, which relates to the style and meaning discussed in Paragraph 3.