In 1899, Swedish chemist Svante Arrhenius developed an equation to answer a long-standing question: why do chemical reactions speed up...

Sentence Structure

• In 1899,
• Swedish chemist Svante Arrhenius
  • developed an equation
    • to answer a long-standing question:
      • why do chemical reactions speed up at higher temperatures?
• The Arrhenius equation,
  • named for its creator,
• (?) an important concept in modern chemistry.
• (?) = have remained/remain/remains/are remaining

Understanding the Meaning

The first sentence gives us the background:

• In 1899, Svante Arrhenius (a Swedish chemist)
  • developed an equation
  • to answer why chemical reactions speed up at higher temperatures

The second sentence tells us about this equation's significance:

• 'The Arrhenius equation, named for its creator...'
  • We learn it's named after Arrhenius

Now here's where we need to fill in the blank:

• 'The Arrhenius equation ______ an important concept in modern chemistry.'

Let's look at our choices:

1. have remained
2. remain
3. remains
4. are remaining

What do we notice?

• The subject doing the action is "The Arrhenius equation"
  • This is singular - we're talking about one equation
• The phrase "named for its creator" sits between the subject and where the verb goes
  • But this phrase is just giving us extra information about the equation
  • It's describing the equation, not changing what our subject is
• Our verb needs to match "The Arrhenius equation" - which is singular

So we need the singular verb form: remains (Choice C).

The complete meaning is:

• The Arrhenius equation continues to be an important concept in modern chemistry
  • This is stating an ongoing fact about its importance

Grammar Concept Applied

Matching Verbs to Their Subjects When Phrases Come Between

When extra information appears between a subject and its verb, the verb must still agree with the actual subject - not with words in the interrupting phrase.

The pattern:

• Subject (singular or plural)
• Interrupting descriptive phrase
• Verb (must match the subject)

Example 1:

• ✓ "The scientist, along with her research team, publishes groundbreaking studies."
• Subject: "The scientist" (singular)
• Interrupter: "along with her research team"
• Verb: "publishes" (singular)

Example 2:

• ✓ "The results, which were unexpected by most experts, challenge current thinking."
• Subject: "The results" (plural)
• Interrupter: "which were unexpected by most experts"
• Verb: "challenge" (plural)

In our question:

• Subject: "The Arrhenius equation" (singular)
• Interrupter: "named for its creator"
• Verb needed: "remains" (singular) ✓

The key is to identify the true subject and ignore the material that comes between the subject and verb, even though that material might contain other nouns or plural words.