Recent studies on bilingualism have yielded fascinating insights. Researchers _____ that children who learn multiple languages simultaneously develop ...

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

• Recent studies on bilingualism
  • have yielded fascinating insights.

• Researchers [?]
  • that children
    • who learn multiple languages simultaneously
  • develop enhanced cognitive flexibility
    • compared to monolingual peers.

• Where [?] = to demonstrate / demonstrate / demonstrating / having demonstrated

Understanding the Meaning

Let's start reading from the beginning:

The first sentence tells us:

• 'Recent studies on bilingualism have yielded fascinating insights.'
  • Studies about people who speak multiple languages have produced interesting discoveries.
  • This sets up the context for what we're about to learn.

Now the second sentence begins:

• 'Researchers ______ that children who learn multiple languages simultaneously...'

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

• to demonstrate
• demonstrate
• demonstrating
• having demonstrated

These are all different forms of the same verb. To see what works here, I need to understand the structure of this sentence!

Let's identify the key parts:

• 'Researchers' = the subject (who is doing something)
• The blank = needs to be the verb (what researchers are doing)
• 'that children who learn multiple languages simultaneously develop enhanced cognitive flexibility compared to monolingual peers' = a complete thought that follows the verb

Now, what do we notice about what's needed here?

• 'Researchers' is our subject
  • It's a plural noun
  • The sentence needs a main verb to tell us what researchers do

• This verb needs to be a "complete" verb form
  • One that can stand on its own as the main action of the sentence
  • One that works with a plural subject like "researchers"

Looking at our options:

• 'to demonstrate' is an infinitive - it can't be the main verb of a sentence
• 'demonstrate' is a complete verb form that matches the plural subject
• 'demonstrating' is an -ing form that would need a helping verb (like "are demonstrating")
• 'having demonstrated' would also need a helping verb to work

So we need: demonstrate (Choice B)

The complete sentence tells us:

• Researchers demonstrate (show/prove) that children who learn multiple languages at the same time develop better cognitive flexibility than children who speak only one language.

GRAMMAR CONCEPT APPLIED

Using Complete Verb Forms as Main Verbs

Every sentence needs a main verb - but not all verb forms can do this job. The main verb must be what we call a "finite" verb (in grammar terms) - a complete form that shows tense and can agree with the subject.

Forms that CAN be main verbs:

• Simple present: "Researchers demonstrate"
• Simple past: "Researchers demonstrated"
• Present perfect: "Researchers have demonstrated"

Forms that CANNOT be main verbs on their own:

• Infinitives (to + verb): "Researchers to demonstrate"
  • These show purpose or work after other verbs
• Participles (-ing forms): "Researchers demonstrating"
  • These need helpers like "are" or work as modifiers
• Perfect participles (having + past participle): "Researchers having demonstrated"
  • These show completed actions but need helping verbs

In this question:

• Subject: "Researchers" (plural)
• Needs: A complete verb form that can stand alone
• Answer: "demonstrate" - simple present tense, agrees with plural subject
• This tells us what researchers do as the main action of the sentence

Think of it this way: if you can put a subject in front of a verb form and it makes a complete statement that could stand alone, it's a complete verb form. "Researchers demonstrate" = complete. "Researchers to demonstrate" = incomplete.