Question 57·Hard·Boundaries
While conducting fieldwork in the dense mangrove forests of Bangladesh, conservation biologist Shaila Parveen documented an otter population so resilient, so ecologically significant, and so ______ that government officials immediately began drafting new protection guidelines.
Which choice completes the text so that it conforms to the conventions of Standard English?
For SAT Standard English punctuation questions, first identify the core sentence structure and check whether the text before the punctuation is a complete sentence; if it is not, you can immediately eliminate colons and semicolons. Next, look for fixed patterns such as "so [adjective] that [result]" or "such [noun] that" where internal punctuation is almost never correct. Finally, check parallel items in a series—if earlier items have no extra punctuation, the third one usually should match them—then choose the option that keeps the structure smooth, grammatical, and consistent.
Hints
Focus on what follows the blank
Look carefully at the word that comes right after the blank. How does that word connect to the adjective you will place in the blank?
Ask if there is a complete sentence before the blank
Read from the beginning of the sentence up to the blank. Could that part stand alone as a complete sentence with a subject and verb and make sense by itself?
Think about common patterns with "so"
In phrases like "so big that" or "so important that," do we usually insert any punctuation between the adjective ("big," "important") and the word "that"?
Check parallel structure in the list
You already have "so resilient" and "so ecologically significant". How should the third part of the list look so that it stays parallel to the first two and flows smoothly into the rest of the sentence?
Step-by-step Explanation
See the structure around the blank
Read the relevant part of the sentence: "an otter population so resilient, so ecologically significant, and so ______ that government officials…" The blank is the third item in a parallel series: "so resilient, so ecologically significant, and so ______." After that, the word "that" introduces what happened as a result.
Recognize the "so … that" pattern
The words after the blank form the common pattern "so [adjective] that [result]." Here it will be "so [word in blank] that government officials immediately began drafting new protection guidelines." In this construction, the adjective and "that" stay directly together as one unit: we normally do not put punctuation between the adjective and "that."
Rule out colon and semicolon
A colon (:) and a semicolon (;) each require a complete sentence (independent clause) before them. Up to the blank, we have "an otter population so resilient, so ecologically significant, and so [word]." That is not a complete sentence; it is just part of the larger sentence serving as the object of "documented." Therefore, options with a colon or semicolon directly after the word in the blank cannot be correct.
Check whether a comma fits here
A comma is not used inside the "so [adjective] that" result structure: we write "so important that" or "so large that," not "so important, that" or "so large, that." The comma would incorrectly break the tight connection between the adjective and "that." So the option with a comma after the word in the blank is also wrong.
Choose the option with no punctuation
Since the blank must complete the third "so [adjective]" in the list and lead directly into the "that" clause, the only answer that follows standard punctuation rules is the choice with no punctuation after the word: D) vital.