Question 122·Medium·Form, Structure, and Sense
Recognized in 2015 by the World Health Organization as a critical breakthrough in disease prevention, _____ has since been administered to millions of children worldwide.
Which choice completes the text so that it conforms to the conventions of Standard English?
For sentence-completion questions testing Standard English conventions, first cover the answer choices and decide what part of speech and role in the sentence the blank must have (subject, verb, noun phrase, etc.). Then pay close attention to introductory phrases and modifiers: the noun right after a comma-opening modifier should be the thing that modifier logically describes. Quickly test each option in the sentence, eliminating any that create dangling or misplaced modifiers, illogical meanings, or shifts from a simple phrase to a full clause when the structure clearly calls for a single noun phrase.
Hints
Identify the grammatical role of the blank
Look at the verb phrase “has since been administered to millions of children worldwide.” The blank comes just before “has,” so what grammatical role must it play in the sentence?
Match the introductory phrase with the right noun
The phrase “Recognized in 2015 by the World Health Organization as a critical breakthrough in disease prevention” should describe the noun that comes right after the comma. Ask yourself: in this context, what thing—not a person or a group—is most likely being recognized as a breakthrough?
Check for misplaced or dangling modifiers
Read the sentence with each option. Does the opening phrase accidentally end up describing the wrong word (like a person or “millions of children”), or does it clearly describe the medical breakthrough itself?
Step-by-step Explanation
Figure out what the blank must do in the sentence
Look at the structure of the sentence:
Recognized in 2015 by the World Health Organization as a critical breakthrough in disease prevention, _____ has since been administered to millions of children worldwide.
The blank comes right before the verb “has been administered.” That means the blank must function as the subject of the sentence.
Also, the opening phrase “Recognized in 2015 by the World Health Organization as a critical breakthrough in disease prevention” is a modifier that should describe the noun (the subject) that comes right after the comma. So the blank must:
- Be a noun or noun phrase (something that can be the subject), and
- Be something that can logically be both recognized and administered in the context of disease prevention.
Test Choice A as the subject
Insert choice A into the sentence:
Recognized in 2015 by the World Health Organization as a critical breakthrough in disease prevention, Dr. Hélène Morin developed a rotavirus vaccine that has since been administered to millions of children worldwide.
Problems:
- The subject right after the comma is Dr. Hélène Morin, so the opening phrase says she was recognized as the breakthrough, which is illogical. The vaccine, not the scientist, is the breakthrough in disease prevention.
- The blank becomes a full clause (“Dr. Hélène Morin developed a rotavirus vaccine that …”), not just a simple subject noun phrase.
So A creates a misplaced modifier and the wrong structure.
Test Choices C and D as the subject
Now plug in C and D to see if they work as the subject and fit the modifier.
Choice C:
Recognized in 2015 by the World Health Organization as a critical breakthrough in disease prevention, since 2015 millions of children have received the rotavirus vaccine, which has since been administered to millions of children worldwide.
Issues with C:
- The phrase after the comma starts with “since 2015 millions of children have received …”, so the modifier is now describing “since 2015 millions of children”, which makes no sense—children are not the “critical breakthrough.”
- The blank is a long clause ending in “which,” not a clean subject for “has since been administered.”
- It also creates repetition about millions of children and “since.”
Choice D:
Recognized in 2015 by the World Health Organization as a critical breakthrough in disease prevention, recognized worldwide, administering the rotavirus vaccine has since been administered to millions of children worldwide.
Issues with D:
- The subject becomes “administering the rotavirus vaccine,” which means “the act of giving the vaccine,” not the vaccine itself. The act of administering cannot itself “be administered.”
- It awkwardly repeats “recognized” and is wordy and confusing.
So both C and D are ungrammatical or illogical as the subject.
Confirm the remaining option fits logically and grammatically
The remaining option is a noun phrase that names the thing actually recognized and administered. Insert it:
Recognized in 2015 by the World Health Organization as a critical breakthrough in disease prevention, the rotavirus vaccine developed by Dr. Hélène Morin has since been administered to millions of children worldwide.
This version:
- Uses a clear noun phrase as the subject.
- Makes the introductory modifier correctly describe the vaccine, which can be recognized as a breakthrough.
- Matches logically with “has since been administered”—a vaccine can be administered to children.
Therefore, the correct answer is B) the rotavirus vaccine developed by Dr. Hélène Morin.