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Question

Difficulty: EasySentence Addition and Deletion Decisions

Many cities are replacing traditional streetlights with light-emitting diode (LED) bulbs to save energy. These modern bulbs consume up to 80 percent less electricity than standard sodium vapor lamps. Although LEDs are highly efficient, some residents complain that the cool, blue-white light they emit is too harsh compared to the warm glow of older lights. Sodium vapor lamps were first developed in the 1930s and became popular for street lighting due to their long lifespan. Consequently, some municipalities are adjusting the color temperature of their new LED installations to address these concerns.

The writer is considering deleting the sentence 'Sodium vapor lamps were first developed in the 1930s and became popular for street lighting due to their long lifespan.' from the passage. Should this sentence be kept or deleted?

  1. A
    Deleted, because it contradicts the statement that LEDs consume less electricity than sodium vapor lamps.
  2. B
    Kept, because it explains why municipalities first began transitioning away from sodium vapor lamps.
  3. Deleted, because it interrupts the paragraph's focus on LED streetlights with irrelevant historical information about sodium vapor lamps.Answer
  4. D
    Kept, because it provides necessary background information about the color temperature of traditional streetlights.

Answer

The correct answer is that the sentence should be deleted because it interrupts the paragraph's focus on LED streetlights with irrelevant historical information about sodium vapor lamps.
The main focus of the paragraph is the modern transition from traditional streetlights to LED bulbs, specifically highlighting energy savings and residents' complaints about the cool color temperature of LEDs. The sentence about the 1930s development and popularity of sodium vapor lamps is a historical tangent that does not contribute to this focus. Therefore, it should be deleted.

Step-by-Step Solution

1
Identify the main topic of the paragraph.
The paragraph focuses on the modern transition from sodium vapor streetlights to energy-efficient LED streetlights, including residents' complaints about LED light quality and how municipalities are addressing them.
To determine if a sentence belongs in a paragraph, you must first understand the paragraph's primary focus.
2
Analyze the content and purpose of the sentence proposed for deletion.
The sentence provides historical context about when sodium vapor lamps were developed (the 1930s) and why they were popular (long lifespan).
This helps determine whether the sentence supports the main topic or introduces a distraction.
3
Evaluate whether the sentence contributes to the main topic or should be deleted.
The historical details about sodium vapor lamps are not relevant to the modern transition to LEDs or the discussion of light temperature. The sentence should be deleted because it interrupts the focus of the paragraph.
Off-topic sentences should be removed to maintain paragraph unity and cohesion.

Key Concept

Evaluating the relevance of details to maintain paragraph unity and cohesion
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Topics

Sentence Addition and Deletion Decisions

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