An inference question tests whether you can finish the text’s reasoning using only the clues it gives. Read the words leading into the blank to see whether you need a conclusion, a prediction, a reason, or a limit. If the text warns about evidence, ask what the warning could affect. Put the clues in a few words, then predict the smallest conclusion they support. A possible outcome still needs support; adding may doesn’t make an extra assumption safe.
Hints
- Hint 1
Read the sentence immediately before the blank and check what the researchers fail to do.
- Hint 2
In the second sentence, compare a first sighting with a full arrival window. What does an entry capture, and what might it leave unrecorded?
- Hint 3
Return to the goal in the first sentence. Ask how the journals’ limits could affect that goal.
Step-by-step
Follow the warning to its consequence
Step 1Find what “do so” refers to
The phrase Researchers who fail to do so points back to adjust for the journals’ inconsistent coverage. What have those researchers failed to do? They haven’t accounted for gaps and uneven observations, so the blank needs a possible consequence of ignoring those limits.
- Step 2
Separate sightings from arrivals
What does a journal entry tell us? The observers recorded only the first robin they saw each spring, so an entry gives one person’s first sighting, not a full picture of the species’ arrival. Their notes were often prompted by chance rather than systematic surveys. That means a difference between years could reflect when someone happened to look, so different sighting dates don’t necessarily mean different arrival dates.
- Step 3
Reject extra assumptions
How far do these clues reach? The reference to the full arrival window for the species shows that the issue is when robins arrive. The choice about migration routes changes that to where they travel, while questioning the modern surveys says how researchers react to surveys the passage never discusses. And years with no journal entry adds an unsupported mistake about whether robins arrived at all.
- Step 4
Connect the limits to the study’s goal
To chart long-term changes, scientists have to compare records across years, and uneven observations can distort that comparison. The choice about how the robins' migration timing has shifted over time names the risk to that comparison without adding a particular error the researchers make. Its may leaves the outcome possible rather than certain. Choice D.