Researcher Dr. Maria Santos, _____ to understand the effects of microplastics on marine ecosystems, conducted a comprehensive five-year study examinin...

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

• Researcher Dr. Maria Santos,
  • [?] to understand the effects of microplastics on marine ecosystems,
• conducted a comprehensive five-year study examining organisms across twelve Pacific Ocean sites.

Understanding the Meaning

Let's start reading:

We have a researcher named Dr. Maria Santos. Then we have a phrase set off by commas.

This is where we have the blank:

• '_____ to understand the effects of microplastics on marine ecosystems'

Let's look at the choices:

• A. seeking
• B. sought
• C. seeks
• D. has sought

These are all different forms of the verb "seek."

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

The sentence continues:

• Dr. Maria Santos 'conducted a comprehensive five-year study examining organisms across twelve Pacific Ocean sites.'

Now let's understand what this complete sentence is telling us:

• Dr. Maria Santos is the researcher who did something
• She conducted (performed) a five-year study
• The study looked at organisms at twelve different Pacific Ocean sites
• The study was examining the effects of microplastics on marine ecosystems

So the phrase in the blank with commas around it is giving us extra information about Dr. Santos - it's telling us her goal or motivation for conducting the study.

What do we notice about the structure here?

• 'Conducted' is the main action verb - it tells us what Dr. Santos actually DID
  • This is what the sentence is fundamentally about: she conducted a study
• The phrase at the blank (between the commas) is describing Dr. Santos
  • It's providing background about WHY she conducted the study
  • It's not another main action - it's additional descriptive information
• Since 'conducted' is already our main verb, the blank can't be another main verb form
  • We need a form that works as a modifier or descriptor
  • This is what a present participle like 'seeking' does - it describes without creating a second main action

So we need A. seeking - it creates a descriptive phrase that tells us about Dr. Santos's purpose, while 'conducted' remains the main action of the sentence.

GRAMMAR CONCEPT APPLIED

Using Participial Phrases to Add Descriptive Information

When you want to add extra information about the subject of your sentence, you can use a participial phrase (called a participial modifier in grammar terms) - a phrase that starts with a verb form ending in -ing or -ed. This phrase is set off by commas and describes the subject without creating a second main action:

Pattern:

• Subject + [participial phrase describing subject] + main verb + rest of sentence

Examples:

• Basic sentence: The scientist published her findings.
• With participial phrase: The scientist, hoping to share her discovery, published her findings.
  • "hoping to share her discovery" = descriptive phrase about the scientist
  • "published" = main verb (the primary action)
• Another example: The students, preparing for their exams, studied late into the night.
  • "preparing for their exams" = descriptive phrase about the students
  • "studied" = main verb (the primary action)

In our question:

• Researcher Dr. Maria Santos, seeking to understand the effects of microplastics, conducted a study.
  • "seeking to understand..." = descriptive phrase about Dr. Santos's purpose
  • "conducted" = main verb (what she actually did)

The key principle: A sentence has one main verb that states the primary action. Participial phrases add supplementary information without competing with that main verb.