In recent years, economists around the world have created new tools that quantify the overall well-being of a country's citizens....

Let's begin by understanding the meaning of this sentence. We'll use our understanding of pause points and segment the sentence as shown - understanding and assimilating the meaning of each segment bit by bit!

Sentence Structure

• In recent years,
  • economists around the world
    • have created new tools
      • that quantify the overall well-being of a country's citizens.
• Economists in India, for example,
  • use an Ease of Living Index.
• This tool
  • [?] economic potential, sustainability, and citizens' quality of life.

Understanding the Meaning

Let's read from the beginning to understand what this passage is telling us:

"In recent years, economists around the world have created new tools that quantify the overall well-being of a country's citizens."

• This tells us about a recent development
• New tools have been created to measure citizen well-being

"Economists in India, for example, use an Ease of Living Index."

• Here we get a specific example of one of these tools
• Notice the verb: "use" (present tense)
• Economists currently use this tool
• The Ease of Living Index is one of the tools mentioned

Now we reach the blank:
"This tool ______ economic potential, sustainability, and citizens' quality of life."

Let's look at our choices:

• We're deciding between different tenses and forms of the verb "measure"
• A. measures (simple present)
• B. had measured (past perfect)
• C. would have measured (conditional perfect)
• D. will have been measuring (future perfect continuous)

What do we need here?

• The subject is "This tool" - that's singular
• The previous sentence tells us economists "use" this tool - present tense
• We're describing what the tool does as its function
• This is a general statement about how the tool works

So we need simple present tense, singular form: measures

The complete meaning is:

• The passage describes new tools for measuring well-being
• Gives India's Ease of Living Index as an example
• Explains what this tool measures: economic potential, sustainability, and quality of life

The correct answer is A.

GRAMMAR CONCEPT APPLIED

Using Simple Present Tense for General Facts and Functions

When you're describing what something does as its general function or characteristic - especially when the context is present tense - you use simple present tense (called "simple present" in grammar terms).

Simple present is used for:

1. General facts and truths:

• The sun rises in the east
• Water boils at 100 degrees Celsius

2. Describing what things do (their function/characteristic):

• This calculator performs complex equations
• The index measures quality of life

3. Maintaining tense consistency in present contexts:

• Scientists use this method. The method produces accurate results. (not "produced" or "will produce")

In this question:

• Context: "Economists...use" (present tense)
• Need: Describe what the tool does
• Answer: Simple present "measures" - maintains consistency and describes the tool's function

The key insight: When describing how something works or what it does in a present-tense context, stick with simple present tense.