A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first sentence because it introduces the main topic. It talks about the Covid-19 pandemic and how it changed learning. This is a general statement that does not need other sentences for context. It sets the stage for the rest of the text. Why other lines are not chosen? The other paragraphs are not chosen because they do not stand alone. For example, Paragraph 2 starts with 'While', which is a conjunction. Paragraph 3 uses 'One inquiry', which refers to something not yet mentioned. Paragraph 4 starts with 'The results', which assumes prior knowledge of results. Therefore, they cannot be the first sentence.

Concluding sentence: Why this is the last line? This paragraph is the last sentence because it wraps up the discussion. It gives the final results of the inquiry and suggests what teachers need. This is a summary style that brings together the earlier points about online learning and teachers' experiences.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects to Paragraph 1 because it continues the topic of online learning. It uses 'While' to show a contrast between what is known and what is not known. This is a logical order because it moves from a general statement about online learning to a specific focus on teachers' perceptions.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 follows Paragraph 2 because it gives an example of research related to teachers' perceptions. The phrase 'One inquiry' shows that it is a specific case that supports the previous statement. This is a broader to specific strategy.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects to Paragraph 3 because it discusses the results of the inquiry mentioned before. The word 'The results' shows that it is a conclusion from the previous paragraph. This is a logical order because it moves from the inquiry to its findings.