Question 43·Hard·Boundaries
Astronomer Vera Rubin collected extensive data on galactic _____ many of her contemporaries remained unconvinced about the existence of dark matter.
Which choice completes the text so that it conforms to the conventions of Standard English?
For sentence-boundary questions, first test whether the text before and after the blank can stand alone as complete sentences. If both are independent clauses, you need a strong separator: a period, a semicolon, or a comma plus a coordinating conjunction. With conjunctive adverbs (however, therefore, nevertheless) between two full sentences, use a period or semicolon before the adverb and a comma after it.
Hints
Check what comes before and after the blank
Read the words before and after the blank and ask: does each side have its own subject and verb, so that it could stand alone as a complete sentence?
Notice what’s the same in all choices
Every answer choice uses the word "nevertheless"; the only difference is the punctuation around it. Focus on how the punctuation affects the way the two parts of the sentence are joined.
Think about sentence boundaries
You are connecting two complete sentences. Is a comma enough to join two independent clauses with a transition word in the middle, or do you need stronger punctuation? Choose the option whose punctuation correctly separates full sentences.
Step-by-step Explanation
Understand the sentence meaning
Read the full sentence around the blank:
"Astronomer Vera Rubin collected extensive data on galactic _____ many of her contemporaries remained unconvinced about the existence of dark matter."
The first part says Rubin collected a lot of data. The second part says many contemporaries still doubted dark matter. These two ideas contrast with each other ("even so, others doubted"), which is why the transition word "nevertheless" appears in every answer choice.
Identify the clause structure
Check whether each side of the blank could stand alone as a sentence:
- Before the blank: "Astronomer Vera Rubin collected extensive data on galactic rotation" – This has a subject ("Astronomer Vera Rubin") and a complete verb phrase ("collected extensive data...") → a complete sentence.
- After the blank: "many of her contemporaries remained unconvinced about the existence of dark matter" – This has a subject ("many of her contemporaries") and a complete verb phrase ("remained unconvinced...") → another complete sentence.
So you are joining two independent clauses and need punctuation strong enough to separate full sentences.
Recall the rule for transitions between two sentences
The word "nevertheless" is a conjunctive adverb (like "however," "therefore," "thus"). When you connect two independent clauses with a conjunctive adverb mid-sentence, the standard pattern is:
- End the first clause with a strong boundary (a period or semicolon).
- Then the conjunctive adverb (here, "nevertheless").
- Then a comma before the rest of the second clause.
A comma by itself (with or without the transition word) is not strong enough to join two independent clauses; that would create a comma splice or a run-on sentence.
Match the rule to the answer choices
Apply the rule:
- "rotation nevertheless" → no boundary before the transition and no comma after it; this runs two sentences together.
- "rotation nevertheless," → comma after the adverb but nothing marks the boundary before it; still a run-on.
- "rotation, nevertheless," → only commas are used between two complete sentences; this is a comma splice.
- "rotation; nevertheless," → semicolon before the transition and comma after it; this correctly joins two independent clauses.
Correct answer: rotation; nevertheless,