A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first line because it introduces the main topic of the text. It talks about playwrights and their different styles. This is a broad overview of what the text will discuss. Why other lines are not chosen? The other paragraphs do not work as the first sentence. For example, Paragraph 2 starts with 'They', which is a pronoun and needs more context. Paragraph 3 starts with 'Others', which also needs context. Paragraph 4 starts with 'Thornton Wilder and Tennessee Williams', which is specific and not general. Paragraph 5 starts with 'However', which shows a contrast and cannot be first.

Concluding sentence: Why this is the last line? This paragraph is the last line because it wraps up the ideas presented in the text. It shows what all the playwrights share, which is their means of expression. This gives a clear conclusion to the discussion.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects to Paragraph 1 because it continues the idea of playwrights. It explains what these playwrights do, which is to create worlds. This shows a logical order from the general idea of different sensibilities to a specific action they take.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects to Paragraph 2 because it introduces a different view. The word 'Others' shows a contrast to the previous idea. This is a logical order because it shows that not all playwrights create the same way.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects to Paragraph 3 because it gives examples of playwrights. It shows the different approaches mentioned in Paragraph 3. This is a logical order because it moves from a general statement to specific examples.
• Pair 4 (Paragraph 4 → Paragraph 5): Paragraph 5 connects to Paragraph 4 because it shows a commonality among the playwrights. The word 'However' indicates a shift from differences to a shared aspect. This is a logical order because it concludes the discussion on their approaches.