Question 98·Medium·Boundaries
Rachel Carson’s groundbreaking book Silent Spring, which warned of the dangers of pesticide ______ helped spark the modern environmental movement.
Which choice completes the text so that it conforms to the conventions of Standard English?
For punctuation and sentence-boundary questions, first strip away modifying phrases (like clauses starting with "which" or "who") to locate the core subject and verb; check that what remains is a complete sentence. Then, identify whether a clause is essential (no commas) or nonessential (needs commas on both sides). Eliminate choices that create fragments or run-ons, and favor the option that cleanly closes off extra information while preserving a clear, grammatical subject–verb connection.
Hints
Check for a complete sentence
Ignore the middle details and see if you can find a clear subject and main verb that form a complete sentence. What is the main thing the book did?
Look closely at the word "which"
The clause starting with "which" adds extra information about the book. Ask yourself: how are extra "which" clauses usually separated from the rest of the sentence?
Think about comma placement
You already have a comma before "which." Where should the matching comma go to close off that extra information so the main action of the sentence can continue?
Be cautious with "and"
If you add "and" in the blank, does the sentence still have a clear main clause outside the "which" phrase, or does it turn into a fragment?
Step-by-step Explanation
Find the main subject and main action
Read the sentence without the middle details:
"Rachel Carson’s groundbreaking book Silent Spring ... helped spark the modern environmental movement."
This shows that the main subject is "Rachel Carson’s groundbreaking book Silent Spring" and the main verb we want to connect it to is "helped spark." Whatever we put in the blank must allow the sentence to get from the subject to the verb smoothly and grammatically.
Recognize the nonessential "which" clause
Look at the phrase starting with "which":
"which warned of the dangers of pesticide use ______ helped spark the modern environmental movement."
Because it starts after a comma (after Silent Spring,), this "which" clause is nonessential information about the book. Nonessential clauses starting with "which" should be surrounded by commas: one before "which" (already there) and one at the end of the clause.
Eliminate choices that create the wrong structure
Consider what happens if we add "and" in the blank (choices A and D):
- With "use and", the sentence becomes a long "which" clause with no clear main clause left over, so the whole sentence is a fragment.
- With "use, and", the sentence still lacks a clean subject–verb connection for the main clause; the structure is awkward and ungrammatical.
So any option that adds "and" in this spot (A or D) should be eliminated.
Decide whether you need a comma or nothing
Now compare the remaining structures:
- Without a comma ("use"), the nonessential "which" clause is never properly closed, and the sentence reads as if "pesticide use helped spark the modern environmental movement," which is not the intended meaning.
- With a comma ("use,"), the nonessential clause is correctly closed: "which warned of the dangers of pesticide use," and then the main clause continues: "helped spark the modern environmental movement."
Therefore, the correct answer is B) use,.