First sentence: Why this is the first line? This paragraph is the first sentence because it introduces the main topic of organising an outdoor film screening. It gives a clear overview of what to do first. It does not need any other sentence for context. Why other lines are not chosen? The other paragraphs do not qualify as the first sentence. Paragraph 2 starts with 'Once', which is a conjunction. Paragraph 3 starts with 'Selecting', which is not a general statement. Paragraph 4 starts with 'Finally', which shows it is not independent.

Concluding sentence: Why this is the last line? This paragraph is the last sentence because it wraps up the process of organising the event. It shows the final step to ensure success.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects with Paragraph 1 because it follows the logical order of steps. After getting permissions, the next step is to choose a location.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects with Paragraph 2 because it continues the process of planning. After ensuring the location is good, the next step is to select the right film.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects with Paragraph 3 because it shows the next step after selecting the film. After choosing the film, promoting the event is important.