A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first sentence because it introduces the main topic about employers and their reluctance to hire young people. It gives a broad overview of the situation without needing prior context. It does not use any pronouns or definite articles that refer to previous information. Why other lines are not chosen? Paragraph 2 starts with 'They', which is a pronoun and does not stand alone. Paragraph 3 starts with 'But', which is a conjunction. Paragraph 4 uses 'the', which assumes prior knowledge. Therefore, they do not qualify as independent sentences.

Concluding sentence: Why this is the last line? This paragraph is the last sentence because it wraps up the discussion about the schemes for young workers. It provides a conclusion about the positive outcomes that companies may see, which reflects the overarching theme of the text.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects with Paragraph 1 because it continues the idea of employers' reluctance. The phrase 'They are sceptical' refers back to 'Employers', showing a clear link between the two.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects with Paragraph 2 using the word 'But', which shows a contrast. It introduces a new idea that some companies are trying to help young workers, which is different from the scepticism in Paragraph 2.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects with Paragraph 3 because it shows the outcome of the schemes mentioned. The phrase 'They can be surprised' refers back to the companies, linking the two ideas.