Question 150·Hard·Boundaries
While astrophysicists once considered Pluto the ninth planet, recent observations—highlighting its irregular orbit and diminutive size—have prompted scientists to reclassify it as a dwarf _____ students still memorize the solar system with Pluto at the end.
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 each stand alone as a complete sentence. If both sides are independent clauses, eliminate choices that use only a comma or no punctuation between them, because those create run-ons. Then pay close attention to transition words like "however" or "nevertheless": they are usually set off with commas and often come after a period or semicolon. Use these rules to quickly rule out incorrect comma and semicolon placements and select the option that cleanly separates ideas while matching standard punctuation patterns.
Hints
Check if both sides of the blank are full sentences
Cover the blank with your finger and see whether the words before it form a complete sentence and whether the words after it could also stand alone as a complete sentence.
Think about sentence boundaries
If both parts are complete sentences, ask yourself: can a simple comma or no punctuation at all correctly connect them, or do you need a stronger break like a period or semicolon?
Focus on the word "nevertheless"
"Nevertheless" is a transition word, not a conjunction like "and" or "but." Consider what punctuation is normally used before and after such a transition when it connects two complete ideas.
Look closely at commas and capitalization
Pay attention to whether "nevertheless" starts a new sentence (capital letter) and whether there is a comma after it before "many students." This can help you distinguish between very similar choices.
Step-by-step Explanation
Identify the clauses around the blank
Read the full sentence and focus on what comes just before and just after the blank.
- Before the blank: "While astrophysicists once considered Pluto the ninth planet, recent observations—highlighting its irregular orbit and diminutive size—have prompted scientists to reclassify it as a dwarf planet"
- After the blank: "many students still memorize the solar system with Pluto at the end."
Now check: both parts can stand as complete sentences (each has a subject and verb and expresses a complete idea). That means we are joining two independent clauses.
Decide what kind of punctuation is needed
When you connect two independent clauses, you cannot just use a comma or nothing at all. On the SAT, your main correct options are:
- A period to make two separate sentences.
- A semicolon to join the two clauses directly.
- A comma only if you also have a coordinating conjunction (like "and," "but," "so").
Here, after "planet" there is no coordinating conjunction like "and" or "but," so a comma alone would be incorrect; we need a stronger boundary (period or semicolon) or correct use of a transitional word.
Understand how "nevertheless" works
"Nevertheless" is a conjunctive adverb (transition word), not a coordinating conjunction. That means:
- You cannot use just a comma before it to join two sentences (that would be a comma splice).
- When it starts or interrupts a clause, it is normally followed by a comma: "Nevertheless, many students..." is the standard form.
So we are looking for punctuation that provides a proper sentence boundary and uses a comma after "Nevertheless" when it introduces the second clause.
Eliminate choices that misuse commas or lack proper sentence boundaries
Check each choice quickly against the rules:
- Any option that only uses a comma to connect the two clauses will create a run-on or comma splice.
- Any option that puts no punctuation between the clauses is definitely a run-on.
- Any option that uses "nevertheless" without a comma after it is awkward and not the standard, correct SAT style.
After applying these rules, only one choice cleanly separates the clauses and punctuates "Nevertheless" correctly.
Confirm the correct answer
The only choice that:
- Ends the first independent clause with a period after "planet",
- Begins a new sentence with a capitalized transition word "Nevertheless",
- And correctly places a comma after "Nevertheless" before the subject "many students",
is "planet. Nevertheless, many", which is the correct answer.