The university's digital archive was launched last year to preserve historical materials. The archive, _____ thousands of documents and photographs...

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

First sentence:

• The university's digital archive was launched last year to preserve historical materials.

Second sentence:

• The archive, [?] thousands of documents and photographs from the 19th century, serves as an invaluable resource for researchers worldwide.

Understanding the Meaning

The first sentence gives us background information:

• The university's digital archive was launched last year to preserve historical materials.
  • So we're learning about a university archive - a collection of historical materials that's now available digitally.

Now let's look at the second sentence. It starts with:

• "The archive,"

This is where we have the blank - right after the comma. Let's look at the choices:

• A: it includes
• B: to include
• C: including
• D: includes

These are different verb forms. To see what works here, let's read the rest of the sentence and understand what it's saying!

The sentence continues:

• "_____ thousands of documents and photographs from the 19th century, serves as an invaluable resource for researchers worldwide."

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

• The part between the commas:
  • "_____ thousands of documents and photographs from the 19th century"
  • This is giving us more details about what the archive contains

• After the second comma:
  • "serves as an invaluable resource for researchers worldwide"
  • This tells us what the archive DOES - its main function

So the complete picture is:

• The sentence is saying: The archive serves as a valuable resource
• Along the way, between commas, it's adding extra information about what the archive contains

What do we notice about the structure here?

• "Serves" is the main verb of the sentence - it's telling us the primary action, what the archive does
• The phrase between the commas is adding descriptive information about the archive
  • It's telling us what the archive includes
  • But it's not the main point - that's why it's set off by commas
• For this kind of descriptive phrase, we need a verb form that can describe or modify, not a form that would try to be another main action

So we need: including

• "Including" is a verb form that can introduce descriptive details
• "The archive, including thousands of documents..., serves..."
• This flows naturally - the descriptive phrase sits between commas, and the main verb "serves" carries the sentence's primary meaning

GRAMMAR CONCEPT APPLIED

Using -ing Verb Forms to Add Descriptive Details

When you want to add extra descriptive information about something you just mentioned, you can use an -ing form of a verb (called a present participle in grammar terms) followed by details, set off by commas:

Pattern:

• Noun (subject), [verb-ing + details], main verb

Example 1:

• The museum, housing over 50,000 artifacts, attracts millions of visitors annually
• "The museum" = subject
• "housing over 50,000 artifacts" = descriptive phrase telling us what the museum contains
• "attracts" = main verb (what the museum does)

Example 2:

• The scientist, drawing on decades of research, proposed a revolutionary theory
• "The scientist" = subject
• "drawing on decades of research" = descriptive phrase about how the scientist worked
• "proposed" = main verb (what the scientist did)

In our question:

• The archive, including thousands of documents and photographs, serves as an invaluable resource
• "The archive" = subject
• "including thousands of documents and photographs" = descriptive phrase telling us what the archive contains
• "serves" = main verb (what the archive does)

The -ing form creates a descriptive phrase that adds information without competing with the main verb of the sentence.