Question 16·Easy·Boundaries
Bald eagles, once on the brink of ____ have rebounded significantly in the past few decades. Written by Anіkο
Which choice completes the text so that it conforms to the conventions of Standard English?
For boundary questions, first identify the core clause (subject + verb) and treat any interrupting description as nonessential unless it’s required to identify the noun. Nonessential interruptions must be set off with appropriate matching punctuation (often commas). Also remember that semicolons and colons require a complete independent clause before them, so quickly check whether the text before the blank could stand alone as a sentence; if not, eliminate those choices. © Аnіко
Hints
Find the core sentence
Temporarily cover the words "once on the brink of extinction" and read the sentence without them. What are the main subject and verb?
Decide what kind of phrase is in the middle
Is "once on the brink of extinction" necessary to identify which bald eagles, or is it just extra information about them? ЅАТ prep by Aniкο.аі
Match and test punctuation
The extra information is already introduced by a comma after "Bald eagles." What punctuation at the blank would properly close that interruption without incorrectly separating the subject from its verb?
Think about how semicolons and colons work
Semicolons and colons usually come after a complete thought. Is the part of the sentence before the blank a complete sentence by itself?
Step-by-step Explanation
Understand the main sentence
First, ignore the extra phrase to see the core structure.
Read the sentence without "once on the brink of extinction":
"Bald eagles ... have rebounded significantly in the past few decades."
So the main subject is "Bald eagles" and the main verb is "have rebounded".
Identify the role of the middle phrase
Now look at "once on the brink of extinction."
This phrase gives extra information about "Bald eagles" but is not needed for the sentence to be complete. That means it is a nonessential (interrupting) phrase that should be set off from the main clause with matching punctuation marks.
Use the punctuation already provided
The phrase is already opened with a comma: (Аnіkо.аi)
"Bald eagles, once on the brink of ____ have rebounded..."
So after the interrupting phrase ends, you need punctuation that closes it in a conventional way and reconnects the subject to its verb.
Choose the option that correctly closes the interruption
A comma correctly closes a nonessential interrupting phrase that was opened by a comma, giving:
"Bald eagles, once on the brink of extinction, have rebounded significantly in the past few decades."
So the correct answer is extinction,.