Question 245·Medium·Boundaries
In 2022, marine biologist Dr. Alexis Chen led an expedition to the Mariana _____ the team discovered several previously unknown species of bioluminescent jellyfish.
Which choice completes the text so that it conforms to the conventions of Standard English?
For boundaries questions, determine whether the text before and after the blank are independent clauses. If both are complete sentences and there’s no coordinating conjunction, you generally need a semicolon or a period (not a comma). Then choose the option whose ending punctuation creates a correct sentence boundary right before the next clause begins.
Hints
Check if both sides form complete sentences
Read the sentence with a pause at the blank. Does the part about Dr. Chen form a complete sentence once you include "Trench"? Does "the team discovered..." also form a complete sentence?
Recall what a comma can and can’t do
A comma by itself cannot separate two independent clauses. What punctuation can separate them when there’s no word like "and" or "but"?
Pay attention to where the boundary actually is
The blank ends right before “the team discovered…”. So ask: what punctuation is immediately before that clause in each option, and is it strong enough?
Step-by-step Explanation
Identify the two clauses
If you choose an answer that ends the first clause, the sentence becomes:
- Clause 1: "In 2022, marine biologist Dr. Alexis Chen led an expedition to the Mariana Trench"
- Clause 2: "there, the team discovered several previously unknown species of bioluminescent jellyfish."
Each clause has a subject and verb and expresses a complete thought, so they are independent clauses.
Determine what punctuation can join two independent clauses
When two independent clauses appear in one sentence with no coordinating conjunction (for, and, nor, but, or, yet, so), they should be separated by a period or a semicolon (a comma alone is not enough).
Test each choice at the boundary
The blank ends right before "the team discovered...", so the punctuation at the end of each answer choice determines whether the boundary is correct:
- If the choice ends with a comma, it creates a comma splice.
- If the choice ends with a semicolon, it correctly joins the independent clauses.
- If the choice ends with a period, it creates two sentences, and the next sentence must start with a capital letter (which matters if the option itself begins the next sentence).
Select the option with correct boundary punctuation
Choices that end with a comma ("Trench there," and "Trench, there,") create a comma splice. The period choice ("Trench. there,") incorrectly starts the new sentence with a lowercase letter.
The semicolon correctly separates the two independent clauses, so the correct answer is Trench; there,.