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 event's planning. It sets the stage for what will happen next. It does not refer to any previous information. Why other lines are not chosen? Paragraph 2 starts with 'To ensure', which is a phrase that suggests a continuation of thought. Paragraph 3 starts with 'The auction', which assumes prior knowledge of the auction. Paragraph 4 starts with 'As a result', which indicates it is a conclusion or result of something that came before.

Concluding sentence: Why this is the last line? This paragraph is the last line because it summarizes the success of the event. It wraps up the main points and shows the positive outcome of all the preparations and efforts made.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 logically connects with Paragraph 1 because it continues the topic of preparations. The phrase 'To ensure' shows that the committee is taking steps to make the event better.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects with Paragraph 2 because it shows the next step after getting donations. The auction is a result of the preparations made in the previous paragraph.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects with Paragraph 3 because it shows the outcome of the auction. The phrase 'As a result' indicates that the success of the auction is due to the advertising efforts mentioned in the previous paragraph.