The ancient Maya developed sophisticated astronomical observatories throughout Central America. Modern researchers study these structures to understan...

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

• The ancient Maya
  • developed sophisticated astronomical observatories
    • throughout Central America.

• Modern researchers
  • study these structures
    • to understand pre-Columbian science.

• The observatories
  • include alignment features
    • that [?] important celestial events,
    • demonstrating the Maya's advanced understanding of astronomy.

Understanding the Meaning

Let's start from the beginning to understand what's happening:

The first sentence tells us:

• 'The ancient Maya developed sophisticated astronomical observatories throughout Central America.'
  • This sets up historical context
  • The Maya built these observatories in the past

The second sentence shifts perspective:

• 'Modern researchers study these structures to understand pre-Columbian science.'
  • Now we're in the present day
  • Researchers today are studying what the Maya built

Now the third sentence focuses on what these observatories contain:

• 'The observatories include alignment features that _____'

This is where we have the blank. Let's look at the choices:

1. tracked (past tense)
2. track (present tense)
3. are tracking (present progressive)
4. have tracked (present perfect)

To see what works here, let's read the rest of the sentence and understand what it's saying!

The complete phrase is:

• 'The observatories include alignment features that _____ important celestial events, demonstrating the Maya's advanced understanding of astronomy.'

Now let's understand what this is telling us:

• 'The observatories include alignment features'
  • This is describing what the observatories contain/have
  • We're talking about physical features that are part of these structures

• 'that _____ important celestial events'
  • This describes what these features do - their function or purpose
  • Like saying "a knife that cuts" or "a lens that magnifies"

• 'demonstrating the Maya's advanced understanding of astronomy'
  • This explains what the features show us about Maya knowledge

What do we notice about the verb we need?

We're describing what these features do - their function or characteristic.

• Even though the observatories were built in the past, we're describing what the features DO as a permanent characteristic
• When we describe what something does as its function or nature, we use present tense
• It's like saying "The pyramids contain chambers" or "Ancient tools serve specific purposes"

The correct answer is B. track

We need present tense because we're describing the function of these features - what they do - not emphasizing when they did it.

GRAMMAR CONCEPT APPLIED

Using Present Tense to Describe Functions and Characteristics

When describing what something does as its function, purpose, or permanent characteristic, we use present tense—even if that thing was created in the past:

Example 1 - Ancient structures:

• The ancient Romans built aqueducts that carry water to cities.
  • "built" = past tense (when they were constructed)
  • "carry" = present tense (what they do as their function)

Example 2 - Historical artifacts:

• The manuscripts contain valuable information about medieval life.
  • Even though the manuscripts were created centuries ago
  • We use present tense to describe what they contain/have

Example 3 - Scientific descriptions:

• The fossils provide evidence of climate change.
  • The fossils were formed long ago
  • But we describe what they do (provide evidence) in present tense

In this question:

• "The observatories include alignment features that track important celestial events"
• We use present tense "track" because we're describing the function of the features
• This is their permanent characteristic, not a time-specific action