Archaeological sites often contain features invisible to the naked eye. Digital imaging methods such as LiDAR and ground-penetrating radar _____...

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

• Archaeological sites often contain features invisible to the naked eye.
• Digital imaging methods such as LiDAR and ground-penetrating radar [?] researchers to map buried structures without excavation.
• This non-invasive approach has revolutionized the study of ancient civilizations.

Understanding the Meaning

Let's start from the beginning:

The first sentence tells us:

• Archaeological sites often contain features invisible to the naked eye.
  • So there are things at these sites that we can't see just by looking.

Now the second sentence:

• "Digital imaging methods such as LiDAR and ground-penetrating radar..."
  • We're talking about digital imaging methods (plural - multiple methods)
  • "Such as LiDAR and ground-penetrating radar" gives us examples of these methods

This is where we have the blank.

Let's look at our choices:

• We need a word to connect "Digital imaging methods" with "researchers to map buried structures"
• The choices show us we're picking between:
  • has allowed / is allowing (singular verb forms)
  • allows (singular verb form)
  • allow (plural verb form)

To see what works here, let's identify the subject clearly:

• The main subject is "Digital imaging methods" - that's plural (methods)
• The phrase "such as LiDAR and ground-penetrating radar" is just giving examples - it's not the subject
• We need to match our verb to "methods"

What do we notice about the structure here?

• The true subject is "methods" (plural)
• There's an interrupting phrase between the subject and where the verb goes
• But the verb must still agree with the actual subject - "methods"
• Since "methods" is plural, we need a plural verb

So we need: allow (the plural form)

Now let's complete the meaning:

• "allow researchers to map buried structures without excavation"
  • These methods make it possible for researchers to map what's buried without digging

The third sentence wraps up:

• "This non-invasive approach has revolutionized the study of ancient civilizations."
  • This way of studying sites (without digging) has transformed how we study ancient cultures

GRAMMAR CONCEPT APPLIED

Matching Verbs to Their Subjects (Subject-Verb Agreement)

The verb in a sentence must match its subject in number - if the subject is plural, the verb must be plural; if the subject is singular, the verb must be singular. This rule still applies even when other words come between the subject and the verb.

The pattern:

1. Find the true subject (the main noun doing the action)
2. Determine if it's singular or plural
3. Match the verb to that subject - not to words that come in between

Common situation where this gets tricky:

When a descriptive phrase or list of examples separates the subject from the verb, you might be tempted to match the verb to the closest noun instead of the actual subject:

• Separated structure: The methods, such as LiDAR and radar, allow...
  • Subject = "methods" (plural)
  • Interrupter = "such as LiDAR and radar" (just examples)
  • Verb = "allow" (plural, matching "methods")
• What doesn't work: The methods, such as LiDAR and radar, allows...
  • This incorrectly matches "allows" to the singular word "radar" nearby
  • But "radar" isn't the subject - "methods" is

In our question:

• Subject: "Digital imaging methods" (plural)
• Interrupter: "such as LiDAR and ground-penetrating radar"
• Correct verb: "allow" (plural, matching "methods")

The key is to identify the core subject and ensure your verb agrees with it, regardless of what words appear in between.