A punctuation question with extra information inside a phrase tests how well you track related words. Find the verb after the blank and ask which words belong with it. Cross out a possible insert, extra information you could remove, and check that the sentence still works. An insert in the middle needs paired commas, dashes, or parentheses; a semicolon needs a full sentence on each side. Track each insert separately, since nearby punctuation may belong to another part.
Hints
- Hint 1
Read through the comma after “plots.” Is the researchers’ statement complete there, and what does the phrase that follows add?
- Hint 2
Look at which word “allowed” goes with. A verb inside a description may belong to that description rather than to the sentence’s main subject.
- Hint 3
Cross out the words that describe how demanding the work was. Ask where those words start and end, and which words must connect when they’re gone.
Step-by-step
Find and test the insert
Step 1Separate the main sentence from the added detail
Read through researchers compared the estimates with field counts from the same plots, which is already a complete statement. What does the phrase beginning with a procedure add? It names the comparison the researchers made, so it’s extra information at the sentence’s end. The comma after plots attaches that whole phrase, not the smaller comment within it.
- Step 2
Find the verb inside the added phrase
What allowed them to determine whether marsh grass had been misclassified as mangrove seedlings? The procedure did, and that begins the clause that describes procedure. A clause is a group of words with a subject and a verb. Now cross out although labor-intensive, the comment about how demanding the work was. The words still say that the procedure allowed the researchers to check their estimates, so the comment is an insert, extra information inside the that clause.
- Step 3
Keep the clause connected
Can a comma go between procedure and that? A noun stays attached to its that clause, so the version with a comma before that breaks that link. A semicolon needs a full sentence on each side, but the version with a semicolon after that cuts the clause off before allowed, its verb.
- Step 4
Match the insert’s two ends
The comment begins after that and ends before allowed them to determine. The comma after labor-intensive closes this insert, so a matching comma must open it after that. The version without a comma after that leaves that closing mark unpaired. The wording procedure that, although labor-intensive, supplies the pair. Choice B.