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 history of football. It gives a broad overview of an important event in football history. It does not use any pronouns or definite articles that refer to previous information. Why other lines are not chosen? Paragraph 2 starts with "However," which is a conjunction. Paragraph 3 uses "Only four years later," which suggests it needs prior context. Paragraph 4 starts with "As an alternative," which also indicates it is not independent. Paragraph 5 begins with "Ironically," which is a transitional phrase and does not stand alone.

Concluding sentence: Why this is the last line? This paragraph is the last sentence because it wraps up the discussion about football's history. It provides a surprising conclusion about the first tournament's winner, which reflects the overall theme of the text.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects to Paragraph 1 using the Connector strategy. The word "However" shows a contrast between the early history of football and its later acceptance into the Olympics.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 follows Paragraph 2 using the Logical Order strategy. It continues the idea of football's growth by showing how it became an official competition after its initial Olympic appearances.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects to Paragraph 3 using the Object Subject Strategy. The focus on amateur competitions in Paragraph 3 leads to the introduction of professional events in Paragraph 4.
• Pair 4 (Paragraph 4 → Paragraph 5): Paragraph 5 follows Paragraph 4 using the Cause and Effect Relationship strategy. It shows the outcome of the professional event by explaining who won the first tournament.