A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first sentence because it is a clear topic sentence. It introduces the main idea of the text, which is about improving a company. It does not need any other sentence for context. Why other lines are not chosen? The other paragraphs are not chosen because they do not stand alone. For example, 'Leave to cook for five years...' starts with a verb and needs context. 'That has been the recipe...' uses 'that' which refers back to something else. 'Add some generous helpings...' starts with a verb and is not a general statement.

Concluding sentence: Why this is the last line? This paragraph is the last sentence because it wraps up the main idea. It summarizes the recipe for success in private equity. It gives a clear conclusion to the text.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects with Paragraph 1 because it continues the idea of improving a company. The phrase 'Add some generous helpings...' shows what to do after taking the company.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects with Paragraph 2 because it explains the result of the actions in Paragraph 2. The phrase 'Leave to cook for five years...' shows what happens after adding debt and incentives.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects with Paragraph 3 because it summarizes the idea. The phrase 'That has been the recipe...' shows that the previous actions lead to a successful outcome.