In his Naturalis historia, Pliny the Elder praised Hipparchus's star catalog, a second-century BCE list of roughly 850 different stars'...

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 his Naturalis historia,
  • Pliny the Elder praised Hipparchus's star catalog,
    • a second-century BCE list
      • of roughly 850 different stars' celestial positions.

• For centuries,
  • scholars dreamed about locating a copy
    • of this legendary lost work [?] fantasy (partially) became reality in 2022,
      • when researchers uncovered traces
        • of the star catalog
        • on a palimpsest,
          • a reused parchment.

Understanding the Meaning

The first sentence gives us the context:

• In his book Naturalis historia,
  • Pliny the Elder (an ancient Roman writer) praised a star catalog by Hipparchus
  • This catalog was a second-century BCE list of about 850 stars and their positions

Now the second sentence:

• 'For centuries, scholars dreamed about locating a copy of this legendary lost work'
  • The star catalog became lost over time
  • For hundreds of years, scholars really wanted to find a copy of it

This is where we have the blank.

Let's look at the choices:

• A: work, that (comma)
• B: work that (no punctuation)
• C: work. That (period - two sentences)
• D: work and that (adds "and")

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

The text continues: 'that fantasy (partially) became reality in 2022, when researchers uncovered traces of the star catalog on a palimpsest, a reused parchment.'

Now let's really understand what this is telling us:

• 'That fantasy'
  • refers back to the dream/fantasy of finding the lost work

• '(partially) became reality in 2022'
  • means the dream sort of came true in 2022
  • the "(partially)" tells us they didn't find the complete thing, but they found something

• 'when researchers uncovered traces of the star catalog on a palimpsest'
  • explains HOW it became reality - researchers found traces of it
  • they found it on a palimpsest (a reused parchment where old text shows through)

So the complete picture is:

• Part 1: For centuries, scholars dreamed about finding this lost work
• Part 2: That dream came true in 2022 when researchers found traces of it

What do we notice about the structure here?

• Look at Part 1: 'For centuries, scholars dreamed about locating a copy of this legendary lost work'
  • This is a complete thought - it has a subject (scholars), a verb (dreamed), and expresses a complete idea
  • It could stand alone as its own sentence

• Look at Part 2: 'That fantasy (partially) became reality in 2022, when researchers uncovered traces of the star catalog on a palimpsest'
  • This is also a complete thought - it has a subject (that fantasy), a verb (became), and expresses a complete idea
  • It could also stand alone as its own sentence

• These are two separate, complete thoughts
  • Yes, they're connected in meaning (the second refers back to the first)
  • But structurally, they're each independent statements

When you have two complete thoughts like this, you need proper separation. You cannot just join them with a comma or run them together with no punctuation.

So we need Choice C: a period

This creates two distinct sentences, cleanly separating the two complete thoughts. "That" then starts the new sentence and clearly refers back to the fantasy mentioned in the previous sentence.

GRAMMAR CONCEPT APPLIED

Separating Two Complete Thoughts

When you have two complete thoughts (called independent clauses in grammar terms) that could each stand alone as sentences, you need to properly separate or connect them. Each complete thought has:

• A subject (who/what is doing something)
• A verb (the action or state)
• A complete meaning (makes sense on its own)

Your options for handling two complete thoughts:

Option 1 - Make two sentences (use a period):

• "Scholars dreamed about finding the work. That fantasy became reality in 2022."
• Clear and correct

Option 2 - Use a semicolon:

• "Scholars dreamed about finding the work; that fantasy became reality in 2022."
• Correct (shows close relationship)

Option 3 - Use comma + coordinating conjunction (and, but, or, nor, for, yet, so):

• "Scholars dreamed about finding the work, and that fantasy became reality in 2022."
• Could work, but "and" might create some confusion here

What you CANNOT do:

Just a comma (comma splice):

• "Scholars dreamed about finding the work, that fantasy became reality."
• This is incorrect - a comma alone cannot join two complete thoughts

No punctuation (run-on):

• "Scholars dreamed about finding the work that fantasy became reality."
• This is incorrect - two complete thoughts cannot run together

How this applies to our question:

• Part 1: "scholars dreamed about locating a copy of this legendary lost work" = complete thought
• Part 2: "that fantasy (partially) became reality in 2022..." = complete thought
• Solution: Use a period to create two clear, separate sentences