Question 236·Medium·Boundaries
Calibrated with ______ the devices can detect even the faintest whale songs from miles away.
Which choice completes the text so that it conforms to the conventions of Standard English?
For punctuation and sentence-boundary questions, first identify the core sentence (subject and verb) and see whether the underlined part is an introductory phrase, a list item, or part of the main clause. Apply a few key rules: introductory phrases usually take a comma before the main clause; do not separate a noun from an essential “that” clause with a comma; and avoid extra or missing commas that break the sentence unnaturally. Then quickly test each option by reading the full sentence in your head, checking it against these rules rather than relying only on what “sounds right.”
Hints
Find the main clause
Read the sentence ignoring the blank: focus on where the main subject and verb start. Where does the real action of the sentence begin?
Look for an introductory phrase
The words before “the devices can detect …” form an introductory phrase. Think about how introductory phrases are usually punctuated before the main clause.
Consider the word “that”
The phrase includes the word “that.” Ask yourself: is the information after “that” essential to identify the “algorithms,” and how are essential “that” clauses usually punctuated?
Match the pattern to an answer choice
You want punctuation that (1) correctly separates the introductory phrase from the main clause and (2) does not break up “algorithms” from its essential description. Which choice fits both conditions?
Step-by-step Explanation
Identify the sentence structure
Look at the whole sentence:
Calibrated with ______ the devices can detect even the faintest whale songs from miles away.
The part starting with “Calibrated with …” is an introductory modifier that describes the devices. After this introductory phrase, the main clause begins: “the devices can detect even the faintest whale songs from miles away.”
Decide where a comma is needed
Introductory phrases that come before the main clause are usually followed by a comma.
So we need a comma at the end of the introductory phrase, right before “the devices.” That means the blank must end with a comma so the sentence reads smoothly:
Calibrated with [introductory phrase], the devices can detect …
Check punctuation around “that”
Inside the blank, all choices include the words “algorithms” and “that filter background noise.” The clause “that filter background noise” tells us which algorithms, so it is essential (restrictive) information.
In Standard English, we do not place a comma between a noun and an essential “that” clause. So there should be no comma before “that.”
Apply both rules to pick the answer
Putting it all together, the correct choice must:
- End with a comma to separate the introductory phrase from “the devices,” and
- Avoid a comma between “algorithms” and “that filter background noise.”
The only option that follows both rules is:
C) algorithms that filter background noise,