Question 114·Hard·Boundaries
Renowned for his meticulous field notes, _____ gathered evidence of natural selection during his expeditions to the Malay Archipelago.
Which choice completes the text so that it conforms to the conventions of Standard English?
For punctuation/boundary questions, first identify the core subject–verb structure to ensure the sentence is complete. Determine whether any middle phrase is essential or extra; if it is extra, it must be enclosed by matching punctuation on both sides. Eliminate choices that mix punctuation marks or fail to properly bracket the interruption.
Hints
Isolate the main sentence
In every option, "Alfred Russel Wallace" is the subject and "gathered" is the verb. The sentence should read smoothly as: "... Alfred Russel Wallace gathered ..." once the descriptive phrase is removed.
Identify the role of the phrase
Ask yourself whether "a contemporary of Charles Darwin" is essential to identify Wallace or merely extra information. Nonessential phrases must be set off from the sentence.
Think about punctuation pairs
Nonessential interruptions must be enclosed by matching punctuation on both sides—either commas or dashes, not a mix.
Check the flow of the sentence
Plug each option into the sentence and read it aloud. Eliminate any option that produces mismatched punctuation or an awkward, unfinished interruption.
Step-by-step Explanation
Find the core sentence
Ignore the descriptive phrase and focus on the core subject–verb structure. With correct punctuation, the sentence reads: "Renowned for his meticulous field notes, Alfred Russel Wallace gathered evidence of natural selection during his expeditions to the Malay Archipelago."
Recognize the type of phrase in the blank
The words "a contemporary of Charles Darwin" provide extra, nonessential information about Alfred Russel Wallace. Nonessential information must be set off with matching punctuation (commas or dashes) on both sides.
Decide how the phrase should be punctuated
Because the phrase interrupts between the subject ("Alfred Russel Wallace") and the verb ("gathered"), the punctuation must mark the start and end of the interruption with the same mark on both sides—either two commas or two dashes—not a mix.
Match the pattern to the answer choices
The only option that brackets the nonessential phrase with matching punctuation is: "Alfred Russel Wallace, a contemporary of Charles Darwin," which yields: "Renowned for his meticulous field notes, Alfred Russel Wallace, a contemporary of Charles Darwin, gathered evidence of natural selection during his expeditions to the Malay Archipelago." Therefore, the correct answer is "Alfred Russel Wallace, a contemporary of Charles Darwin,".