A punctuation question with extra information tests how you separate an added description from the main sentence. Find where any opening description ends, then find who or what the sentence is about and what happens. Cross out the added description and check that a complete sentence remains. A description in the middle needs matching commas, dashes, or parentheses at both ends. Track each pair separately, because a nearby mark may belong to a different part of the sentence.
Hints
- Hint 1
Look at the comma before the blank. Does it end the opening description, or start a description within the main sentence?
- Hint 2
Use gathered to find the main sentence, then cross out the added description. Find where that description begins and ends so you can check whether the marks match.
Step-by-step
Cross out the insert and match marks
Step 1Separate the opening description
The opening phrase Renowned for his meticulous field notes, describes someone, while gathered is the main verb, the word telling us what he did. To choose the punctuation, ask what the comma before the blank does. It ends the opening description, rather than opening extra information within the main sentence.
- Step 2
Test the added description
Which words in the completion belong to the main sentence? Alfred Russel Wallace names the person who gathered the evidence, while a contemporary of Charles Darwin adds a description of him. Let's cross out the added description: Wallace still gathered evidence of natural selection, so we still have a complete sentence. The Darwin phrase is an insert, extra information we can remove without breaking the sentence.
- Step 3
Find both ends
Where does this insert start and end? It starts after Wallace and ends after Darwin, right before gathered evidence of natural selection. An insert in the middle needs matching marks at both ends: commas, dashes, or parentheses. The version with no mark after Wallace leaves the insert's start unmarked; the comma before his name belongs to the opening description.
- Step 4
Match the punctuation
Compare the marks after Wallace and Darwin. The version with a dash then a comma and the version with a comma then a dash mix marks instead of making a matching pair. The version with two commas closes the added description before gathered evidence of natural selection, so the main sentence can continue. Choice B.