First sentence: Why this is the first line? This paragraph is the first sentence because it introduces the main topic of making coffee. It sets up the main idea without going into details. It does not use any words that need prior context. Why other lines are not chosen? Paragraph 2 starts with 'Grinding', which is not a general statement. Paragraph 3 starts with 'Use', which is also not general. Paragraph 4 starts with 'Once', which suggests it needs prior information. All these do not stand alone.

Concluding sentence: Why this is the last line? This paragraph is the last sentence because it wraps up the process of making coffee. It gives the final step and shows the result of all the previous actions.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): This pair connects because the second paragraph gives more detail about the first step in making coffee. It follows a logical order where selecting beans leads to grinding them.
• Pair 2 (Paragraph 2 → Paragraph 3): This pair connects because after grinding, the next step is to use the right water. It shows a logical order of steps in making coffee.
• Pair 3 (Paragraph 3 → Paragraph 4): This pair connects because after using the right water, the next step is to brew the coffee. It follows a logical order of making coffee.