A punctuation question with a description tests how you set off extra information. Read around the blank to find both ends, then try crossing out the description to check whether the remaining words make a complete sentence. Commas and dashes can set off extra information, with matching marks at both ends in the middle of a sentence. A semicolon joins complete sentences, while a colon follows a complete sentence to introduce an explanation or list. Checking only the blank can miss a mark farther away.
Hints
- Hint 1
Read ahead from the blank to transformed and look for the end of the description.
- Hint 2
Try crossing out the description between Marie's name and transformed. Then check the punctuation rules against the words on both sides of the blank.
Step-by-step
Find the insert and match its marks
Step 1Find the description's end
Read ahead to a pioneering geologist and cartographer,, the description following Marie's name. Since the blank comes before it, where does the description end? It ends before transformed, which tells us what Marie did, and a printed comma marks that end.
- Step 2
Cross out the description
Try crossing out the description and reading Marie's name straight into transformed thousands of depth measurements. Does the sentence still work? Yes, because it still tells us that Marie transformed the measurements into maps. The sentence still has everything it needs, so the description is an insert, extra information that we can remove without breaking the sentence.
- Step 3
Add the matching opening mark
In the middle of a sentence, an insert must open and close with matching marks. What does the comma after cartographer, call for at the beginning? The opening mark must also be a comma, so the version with a comma after Tharp adds the missing half of the pair. Choice B.