Biochemist Rosalind Franklin's _____ instrumental to Watson and Crick's 1953 discovery of DNA's double helix structure, have only in recent...

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

• Biochemist Rosalind Franklin's contributions[?] instrumental to Watson and Crick's
• 1953 discovery of DNA's double helix structure,
• have only in recent decades received the widespread recognition they deserved,
• having been largely overshadowed by her male colleagues for nearly thirty years.

Where [?] represents:

• A: , were
• B: ,
• C: were
• D: , had been

Understanding the Meaning

Let's start reading from the beginning:

"Biochemist Rosalind Franklin's contributions"

• Okay, we're talking about her contributions to science.

This is where we have the blank.

Let's look at the choices:

• Some have just a comma
• Some add "were" or "had been" after the comma
• One has "were" without a comma

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

"instrumental to Watson and Crick's 1953 discovery of DNA's double helix structure"

• This tells us how important her contributions were - they were crucial to Watson and Crick's famous discovery.

Then after another comma:

"have only in recent decades received the widespread recognition they deserved"

• So her contributions have (finally) received recognition - but only in recent decades.

"having been largely overshadowed by her male colleagues for nearly thirty years"

• This explains why the recognition came so late - her work was overshadowed by male colleagues for about 30 years.

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

• The subject of the sentence: "contributions"
• The main action being described: "have received"
  • This is telling us what happened to the contributions
  • They received recognition (but only recently)
• So what about "instrumental to Watson and Crick's 1953 discovery"?
  • This is describing the contributions - telling us more about them
  • It's giving us additional information about what kind of contributions they were

What do we notice about the structure here?

• We have: subject + describing phrase + main verb
  • "contributions" = subject
  • "instrumental to..." = phrase describing the contributions
  • "have received" = main verb
• When you insert a describing phrase between a subject and its main verb, you need to set it off with commas on both sides
  • One comma after "contributions" (what we're filling in)
  • One comma after "structure" (already there)
• We should NOT add "were" or "had been" because that would create a second main verb
  • If we said "contributions were instrumental... have received..." we'd have two main actions competing: "were" and "have received"
  • That creates a structural problem - one subject can't have two separate main verbs without proper connection

So we need just the comma - Choice B.

GRAMMAR CONCEPT APPLIED

Using Commas to Set Off Descriptive Phrases

When you want to add descriptive information about your subject before getting to the main verb, you can insert a describing phrase and set it off with commas (this is called a non-restrictive modifier or appositive phrase in grammar terms):

Pattern:

• Subject, describing phrase, main verb

Example 1:

• Without the phrase: "The discovery changed medicine."
• With describing phrase added: "The discovery, a breakthrough in cancer treatment, changed medicine."
  • Subject: "discovery"
  • Describing phrase: "a breakthrough in cancer treatment"
  • Main verb: "changed"

Example 2:

• Without the phrase: "The students passed the exam."
• With describing phrase added: "The students, exhausted from studying all night, passed the exam."
  • Subject: "students"
  • Describing phrase: "exhausted from studying all night"
  • Main verb: "passed"

In our question:

• Subject: "contributions"
• Describing phrase: "instrumental to Watson and Crick's 1953 discovery of DNA's double helix structure"
• Main verb: "have received"

The key is recognizing that you're NOT creating a separate clause with its own verb (like "were instrumental") - you're just adding a descriptive phrase that needs to be set off with commas so the reader can find the main verb.