A punctuation question tests how marks separate extra information from the rest of a sentence. Find where a description starts and where the surrounding sentence continues, then use the cross out test: the sentence must still be complete without it. Check each mark's job: commas and dashes pair up around extra information. A semicolon joins complete sentences, while a colon follows a complete sentence and introduces an explanation or example.
Hints
- Hint 1
Look for where the description of the otter ends. Which words tell what happened during the tour?
- Hint 2
Try crossing out the otter’s description and reading what's left. How does the sentence continue after that description?
Step-by-step
Find the insert and match its marks
Step 1Find where the description starts
The dash in the river otter— starts a semiaquatic mammal native to a place, so start by checking whether that description is extra information. What do those words do? They give another description of the otter rather than tell us what the naturalist did. That's a likely insert, extra information the sentence can do without, and the blank asks us how to mark its end.
- Step 2
Find the end and cross it out
Where does the sentence pick up again? In as it slid playfully down the muddy riverbank, as means while, so these words tell us when the naturalist pointed out the otter. They don't belong to the description of where the mammal is native. Cross out that description, and the naturalist pointed out the river otter connects directly to the words about when it happened, forming a complete sentence. That test shows the insert ends before the words about when it happened.
- Step 3
Match the closing mark
The opening dash needs a closing dash because this description sits inside a sentence that continues after it. Which mark is already fixed in the text? The dash in the river otter— opened the insert, and a dash must close it before the words about the otter sliding. North America— adds that closing mark without breaking the connection between what the naturalist did and when the otter slid. Choice A.