In his 1863 Gettysburg Address, Abraham Lincoln's references to the founding fathers _____ the nation's enduring commitment to equality and...

Sentence Structure

• In his 1863 Gettysburg Address,
    • Abraham Lincoln's references
                      • to the founding fathers
        • (?) [reaffirms/is reaffirming/has reaffirmed/reaffirm]
            • the nation's enduring commitment
                            • to equality and democratic principles.

Understanding the Meaning

Let's start reading from the beginning:

'In his 1863 Gettysburg Address'
    · This sets the context - we're talking about Lincoln's famous speech.

'Abraham Lincoln's references to the founding fathers'
    · This is what we're focusing on: his references (the mentions he made)
      about the founding fathers.
    · Notice "references" is plural - he made multiple references.

Now here's where we need to fill in the blank:
    · 'Abraham Lincoln's references to the founding fathers _____
       the nation's enduring commitment...'

Let's look at our choices:
    · We're deciding between different forms of the verb "reaffirm"
    · Some are singular (reaffirms, is reaffirming, has reaffirmed)
    · One is plural (reaffirm)

What do we notice about the structure here?
    · The subject of this sentence is "references" - that's what's doing the action
    · "Abraham Lincoln's" is just telling us whose references they are
    · "References" is plural - we're talking about multiple references
    · So the verb needs to match: it needs to be plural too

So we need reaffirm - the plural form that matches with "references."

Now let's read the rest to see the complete picture:
    · The references reaffirm "the nation's enduring commitment to equality
      and democratic principles"
    · In other words, by mentioning the founding fathers, Lincoln was
      reinforcing America's ongoing dedication to equality and democracy.

GRAMMAR CONCEPT APPLIED

Matching Verbs to Their Subjects in Number

The action word in a sentence (the verb) needs to match what's doing the action (the subject) in whether it's singular or plural:

When the subject is plural, use the plural verb form:

• The students study together. ✓
• The students studies together. ✗

When the subject is singular, use the singular verb form:

• The student studies alone. ✓
• The student study alone. ✗

Watch out for words that come between the subject and verb:

• The box of cookies sits on the table. (singular subject "box")
• The cookies in the box sit on the table. (plural subject "cookies")

In our question:

• Subject: "references" (plural)
• Verb needed: "reaffirm" (plural)
• Don't be distracted by "Abraham Lincoln's" - that just tells us whose references
• Don't be distracted by "to the founding fathers" - that describes the references but doesn't change that it's plural

The pattern is clear: references (plural) → reaffirm (plural)