A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first sentence because it introduces the main topic of students changing countries for university studies. It is a general statement that sets the stage for the rest of the text. 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, so it cannot be independent. Paragraph 3 starts with 'They' too, which makes it dependent. Paragraph 4 starts with 'Some' which is also not independent. Paragraph 5 starts with 'Whatever' which is not a general statement. All these reasons make them not suitable as the first sentence.

Concluding sentence: Why this is the last line? This paragraph is the last sentence because it concludes the text by summarizing the main idea. It reflects on the reasons students study abroad and emphasizes the outcome of their efforts.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects to Paragraph 1 because it explains that students have different reasons for studying abroad. This shows a logical order from a general statement to a more specific detail.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects to Paragraph 2 because it gives examples of the reasons students choose universities. This follows the broader to specific strategy, moving from a general idea to specific examples.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects to Paragraph 3 because it introduces another reason why students study abroad. This shows a logical order as it continues the theme of reasons for studying overseas.
• Pair 4 (Paragraph 4 → Paragraph 5): Paragraph 5 connects to Paragraph 4 because it summarizes the overall idea that many students pursue their dreams of education for various reasons. This shows a conclusion that wraps up the discussion.