A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first sentence because it introduces the main topic of traffic problems in Millau. It does not need another sentence for context. It is a general statement about the situation before the bridge was built. Why other lines are not choosen? The other paragraphs are not chosen because they do not stand alone. For example, Paragraph 2 starts with "Its location" which needs context. Paragraph 3 starts with "However" which is a conjunction. Paragraph 4 starts with "In addition" which also needs prior information. Paragraph 5 starts with "After all" which is a transitional phrase.

Concluding sentence: Why this is the last line? This paragraph is the last sentence because it wraps up the discussion about the Millau Bridge. It gives a final point about its height and completion time, which summarizes the success of the bridge.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects to Paragraph 1 because it gives more detail about why traffic was a problem. It explains the location that caused the traffic issues. This shows a logical order from a general problem to a specific reason.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects to Paragraph 2 because it shows the solution to the traffic problem mentioned in Paragraph 2. The word "However" indicates a change from the problem to the solution, which is a clear logical order.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects to Paragraph 3 because it adds more information about the bridge. It talks about the bridge's success in engineering, which is related to the construction mentioned in Paragraph 3. This shows a broader to specific strategy.
• Pair 4 (Paragraph 4 → Paragraph 5): Paragraph 5 connects to Paragraph 4 because it gives an example of why the bridge is a great success. It mentions that it is the tallest bridge and was completed early, which supports the claim made in Paragraph 4. This shows a topic example strategy.