Question 20·Medium·Boundaries
When the nineteenth-century photographer Julia Margaret Cameron took portraits, she often used a technique considered radical at the _____ letting her subjects move slightly instead of demanding complete stillness, a practice that unsettled many critics.
Which choice completes the text so that it conforms to the conventions of Standard English?
For boundaries questions, first classify what comes after the blank: an independent clause, a dependent clause, or a nonrestrictive modifier. Then apply the punctuation rule that fits: semicolons join two independent clauses; colons introduce explanations/lists after an independent clause; and nonrestrictive "which" clauses are set off with commas (or with paired dashes/parentheses when appropriate).
Hints
Identify the "which" clause
Look at the words starting with "which involved." Are they essential to identify the technique, or are they extra information?
Check whether the sentence continues afterward
After the "which involved..." information, does the sentence keep going (with more words), or does it end right there?
Use matching punctuation
Nonessential clauses inserted into the middle of a sentence must be set off with matching punctuation (commas with commas, dashes with dashes). See what punctuation appears after the clause and make the beginning match.
Step-by-step Explanation
Identify the sentence structure around the blank
The main clause is "she often used a technique considered radical at the _____." Immediately after the blank comes "which involved letting her subjects move slightly..." and the sentence continues after that clause: ", a practice that unsettled many critics."
Determine what the "which" clause is doing
"Which involved letting her subjects move slightly instead of demanding complete stillness" is a nonrestrictive relative clause adding extra (nonessential) information about the technique.
Match punctuation to a nonrestrictive insertion
A nonrestrictive "which" clause inserted into the middle of a sentence should be framed by matching punctuation. Since the text after the clause already uses a comma ("stillness, a practice..."), the punctuation before the clause should also be a comma.
A semicolon cannot be used because what follows is not an independent clause. A colon is not appropriate because it would introduce a fragment here. A dash would require a second dash later to close the interruption.
Select the correct option
The correct completion is "time, which involved," producing: "...radical at the time, which involved letting her subjects move slightly instead of demanding complete stillness, a practice that unsettled many critics."