Question 43·Easy·Boundaries
In a recent sustainability report, researchers documented numerous _____ of cities using rooftop gardens to lower energy costs.
Which choice completes the text so that it conforms to the conventions of Standard English?
For boundary questions, identify whether the words after the blank are essential to the grammar and meaning of what comes right before. If what follows is an essential modifier (like a prepositional phrase starting with "of" that completes a noun), do not insert punctuation that breaks the phrase. Use a colon or dash only when the text before the mark is a complete thought and what follows is clearly introduced material (a list, explanation, or aside).
Hints
Try it with no punctuation
Read the sentence with the blank filled by the plain word "examples". Does it sound complete and natural?
Check the word after the blank
The next word is "of." Decide whether "of cities..." is essential to the meaning of "examples" or just extra information.
Use punctuation only after a complete thought
Colons and dashes typically come after a complete sentence or clause and introduce added material. Ask whether the words before the blank are a complete thought by themselves.
Step-by-step Explanation
Read the sentence with a seamless noun phrase
Read the sentence as if the blank is filled with the plain word:
"In a recent sustainability report, researchers documented numerous examples of cities using rooftop gardens to lower energy costs."
This reads smoothly and keeps "examples of cities..." together as one noun phrase.
Identify the function of what follows
The words after the blank start with "of cities," a prepositional phrase that answers: examples of what?
So "of cities using rooftop gardens..." is essential information that completes the meaning of "examples."
Eliminate punctuation that would create an incorrect break
- A colon (:) should follow a complete independent clause and introduce what comes next.
- A comma (,) would suggest a nonessential pause or interruption.
- A dash (—) creates an even stronger break, typically for an aside.
None of these fits because we do not want to separate "examples" from its essential modifier "of cities..."
Select the option that keeps the noun phrase intact
Choose examples (with no punctuation), so the sentence reads "numerous examples of cities using rooftop gardens..."