The ancient pottery fragments discovered in the Mesopotamian valley date back to 3500 BCE, making them among the earliest examples...

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 pottery fragments
• discovered in the Mesopotamian valley
  • date back to 3500 BCE,
    • making them among the earliest examples of ceramic art
      • in the region.

• Historians had long assumed
  • these artifacts were purely functional in nature [?]
• recent chemical analysis reveals
  • decorative pigments
    • that suggest ceremonial use.

Understanding the Meaning

The first sentence gives us the context:

• 'The ancient pottery fragments discovered in the Mesopotamian valley date back to 3500 BCE'
  • We're talking about very old pottery from Mesopotamia
  • It dates to 3500 BCE

• 'making them among the earliest examples of ceramic art in the region'
  • So these are some of the earliest ceramic pieces ever found there

Now the second sentence tells us about what historians thought:

• 'Historians had long assumed these artifacts were purely functional in nature'
  • For a long time, historians believed these pottery pieces were just practical items
  • "Functional" means they were used for everyday purposes, not for decoration or ceremony

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

1. nature but (no comma)
2. nature, (just a comma)
3. nature, but (comma + but)
4. nature (nothing)

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

• 'recent chemical analysis reveals decorative pigments that suggest ceremonial use'
  • New scientific testing shows there were decorative colors on the pottery
  • This suggests the pottery was used for ceremonies, not just everyday practical purposes

Now let's understand what we have here:

• First part: 'Historians had long assumed these artifacts were purely functional in nature'
  • This is a complete thought on its own
  • It has a subject (Historians) doing an action (had assumed)
  • It could stand alone as a sentence

• Second part: 'recent chemical analysis reveals decorative pigments that suggest ceremonial use'
  • This is also a complete thought on its own
  • It has a subject (recent chemical analysis) doing an action (reveals)
  • It could also stand alone as a sentence

What do we notice about the relationship?

• These two complete thoughts are presenting contrasting information:
  • What historians thought: just functional/practical
  • What the science shows: ceremonial/decorative
• This is a direct contradiction - the new evidence goes against the old assumption

So we need:

• A way to connect two complete thoughts
• Something that shows they contrast with each other

The answer is: comma + but

• "But" signals the contrast between the ideas
• The comma before "but" is required when connecting two complete thoughts with a word like "but"

GRAMMAR CONCEPT APPLIED

Connecting Two Complete Thoughts That Contrast

When you have two complete thoughts (called independent clauses in grammar terms) and you want to show that they contrast with each other, you need both a comma AND a contrasting word like "but":

Pattern: [Complete Thought], but [Complete Thought]

Example 1:

• The forecast predicted rain, but the day was perfectly sunny.
• First complete thought: "The forecast predicted rain"
• Contrasting word: "but"
• Second complete thought: "the day was perfectly sunny"

Example 2:

• Scientists expected the experiment to fail, but the results exceeded all expectations.
• First complete thought: "Scientists expected the experiment to fail"
• Contrasting word: "but"
• Second complete thought: "the results exceeded all expectations"

In our question:

• Historians had long assumed these artifacts were purely functional in nature, but recent chemical analysis reveals decorative pigments that suggest ceremonial use.
• First complete thought: historians' assumption about functional use
• Contrasting word: "but"
• Second complete thought: what chemical analysis actually revealed
• The comma before "but" is essential when connecting these two complete thoughts

Key points to remember:

• Both parts must be able to stand alone as complete sentences
• The comma comes before "but" (not after)
• The word "but" signals that the second thought contrasts with or contradicts the first
• You need BOTH the comma AND the "but" - one without the other creates an error