First sentence: Why this is the first line? This paragraph is the first line because it introduces the main topic about human communication. It does not refer to any previous information. It sets the stage for the discussion about reading. Why other lines are not choosen? Paragraph 2 starts with "So" which is a conjunction, so it cannot be independent. Paragraph 3 also starts with "So" and uses a pronoun "we" which refers back to something not mentioned before. Paragraph 4 starts with "So" and uses the definite article "the" which assumes prior knowledge.

Concluding sentence: Why this is the last line? This paragraph is the last line because it wraps up the discussion about reading. It shows that even if we have the ability, we still need help to read. This gives a final thought on the topic.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects with Paragraph 1 because it continues the idea of special abilities. The phrase "So reading is a very special ability" shows a logical flow from the first paragraph.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects with Paragraph 2 because it gives more details about reading. The word "because" shows that it explains why reading is special.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects with Paragraph 3 because it talks about the help needed to read. The word "So" shows a continuation of the thought about reading.