Question 33·Hard·Form, Structure, and Sense
In the field of conservation biology, a network of citizen scientists stationed across multiple continents ______ crucial data on migratory bird populations, enabling researchers to detect shifts in flight patterns with unprecedented speed.
Which choice completes the text so that it conforms to the conventions of Standard English?
For verb-agreement questions, first strip the sentence down to its core: cross out introductory phrases and prepositional phrases (like "of citizen scientists") to find the main subject. Decide if that subject is singular or plural, then check the time frame (general truth, ongoing habit, specific past event, etc.) to choose the appropriate tense. Finally, eliminate any choice whose verb does not match both the subject’s number and the sentence’s time frame, always favoring the simplest tense that fits the meaning.
Hints
Locate the true subject
Ignore the phrase "In the field of conservation biology" and the words after "of" for a moment. What is the main noun that the verb must agree with?
Decide on singular vs. plural
Is the main subject one thing or more than one? That will tell you whether you need a singular or plural verb form.
Check the time frame of the action
Is the sentence talking about a single completed action in the past, or about what typically happens now in general? Choose the verb tense that matches that idea.
Compare how each choice fits
For each option, ask: Does this form agree in number with the subject, and does its tense match an ongoing, general activity?
Step-by-step Explanation
Find the main subject of the sentence
Ignore the introductory phrase and prepositional phrases. The core of the sentence is:
"... a network of citizen scientists ... ______ crucial data..."
The head noun (the main subject) here is "network," not "citizen scientists." The phrase "of citizen scientists" only describes what kind of network it is.
Decide if the subject is singular or plural
Ask: Is "a network" one thing or many things?
- "Network" refers to a single organized system or group.
- It is also preceded by "a," which signals a singular noun.
So the subject is singular and needs a singular verb form.
Decide which tense fits the meaning
The sentence describes what this network does in general in the field of conservation biology:
"...enabling researchers to detect shifts in flight patterns with unprecedented speed."
This sounds like a current, ongoing role or function, not a one-time past action. For general, ongoing facts or routines, English uses the simple present tense (like "does," "makes," "collects").
So we need a verb that is both singular and in the simple present tense.
Match the correct choice to the subject and tense
Now check each option:
- gather – simple present plural verb (used with "they," "scientists")
- has gathered – singular, but present perfect (emphasizes completed action up to now, not a general ongoing role)
- gathers – simple present singular verb (used with "it," "a network")
- are gathering – present progressive plural verb (used with "they")
Only "gathers" is both singular and simple present, matching the subject "a network" and the ongoing, general action.
Correct answer: C) gathers.