Question 80·Medium·Boundaries
In her latest article, historian Laila Garner argues that the "Pine Needle Letters"—some of the oldest pieces of correspondence ever discovered—were preserved by an accident of climate. The letters’ ______ thin, fibrous layers of processed cedar bark—remained dry for centuries in the arid caves of the Anatolian plateau.
Which choice completes the text so that it conforms to the conventions of Standard English?
For punctuation/boundary questions, first strip away any middle phrases to find the core sentence and check that it is complete. Then identify whether the interrupted part is nonessential; if so, make sure it’s set off by matching punctuation on both sides (commas with commas, dashes with dashes, etc.), and avoid semicolons unless both sides are full independent clauses. This structural check is often faster and more reliable than “what sounds right.”
Hints
Find the main sentence without the description
Ignore the phrase “thin, fibrous layers of processed cedar bark” for a moment. What is the basic subject–verb–object structure of the second sentence if you remove that phrase?
Notice the descriptive phrase in the middle
The phrase “thin, fibrous layers of processed cedar bark” is extra information describing the letters’ material. In English, such interrupting descriptions are usually set off by a matching pair of punctuation marks.
Use the punctuation that’s already there
Look at the punctuation mark that already appears right after the word “bark.” Which answer choice at the blank creates a properly matching pair of punctuation marks around the descriptive phrase while still leaving a complete sentence when that phrase is removed?
Step-by-step Explanation
See the core structure of the sentence
Focus on the second sentence:
The letters’ ______ thin, fibrous layers of processed cedar bark—remained dry for centuries in the arid caves of the Anatolian plateau.
The phrase “thin, fibrous layers of processed cedar bark” is describing what the letters’ material is like. It is extra, descriptive information in the middle of the sentence, not the main subject–verb structure.
Identify the interrupter (nonessential) phrase
If you temporarily remove the descriptive middle phrase, you should still have a complete sentence:
The letters’ ______ remained dry for centuries in the arid caves of the Anatolian plateau.
That means the descriptive part — “thin, fibrous layers of processed cedar bark” — is a nonessential/appositive phrase that interrupts the main clause and must be set off with matching punctuation marks (commas with commas, or dashes with dashes, etc.).
Match and test the punctuation
You are told there is already a dash after “bark”:
... thin, fibrous layers of processed cedar bark—remained ...
So the blank must provide matching punctuation to close off the descriptive phrase properly. Also, when you remove the descriptive phrase, the sentence around it should read smoothly:
The letters’ parchment sheets remained dry for centuries in the arid caves of the Anatolian plateau.
The only choice that (1) leaves this core sentence correct and (2) matches the dash after “bark” is D) parchment sheets—.