Question 57·Hard·Form, Structure, and Sense
On display at the new science museum is a robotic swarm; _____ synchronized movements demonstrate recent advances in autonomous navigation.
Which choice completes the text so that it conforms to the conventions of Standard English?
For pronoun and apostrophe questions, first find the noun the pronoun refers to and decide if it is singular or plural. Then decide the pronoun’s job: is it showing possession (like "its," "his," "their") or acting as a subject with a verb (like in contractions "it's" = "it is")? Eliminate any choices whose number (singular/plural) does not match the noun, and be very cautious of apostrophes: on the SAT, words like "it's" and "they're" almost always function as contractions, not possessive forms, so they will be wrong whenever the sentence needs a possessive pronoun before a noun.
Hints
Check what the pronoun refers to
Look back at the noun before the semicolon. Is it talking about one group or many separate things? Your pronoun must match that in number (singular vs. plural).
Figure out the pronoun’s role
Ask yourself: does the blank need to show who owns the "synchronized movements," or does it need to act as a subject with a verb like "is" or "are"?
Watch out for apostrophes and contractions
Remember that forms with apostrophes like "it's" and "they're" usually stand for two words (like "it is" or "they are"). Decide whether that fits the grammar of this sentence right before "synchronized movements demonstrate."
Step-by-step Explanation
Identify what the blank refers to
Look at the noun just before the semicolon: "a robotic swarm". The pronoun in the blank must refer back to this noun.
Even though a swarm is made up of many robots, the word "swarm" itself is treated as singular in this sentence (like "team" or "group"). So we need a pronoun that can stand for one thing, not many.
Decide the pronoun’s job in the sentence
Read the sentence structure: "... a robotic swarm; _____ synchronized movements demonstrate ..."
The blank comes right before the noun "synchronized movements". That means the word in the blank is showing who owns or has these movements. So the pronoun must be possessive (showing ownership), not a subject doing an action and not a contraction with a verb.
We need a singular possessive pronoun that can replace "the swarm's" before "synchronized movements."
Match the meaning and grammar to the answer choices
Now test each choice as a pronoun for "swarm" and see if it is a singular possessive:
- One choice is the singular possessive pronoun that means "belonging to it" and does not use an apostrophe.
- One choice is a contraction of "it is" or "it has," which would wrongly insert a verb.
- One choice is a plural possessive pronoun, which does not match the singular noun "swarm."
- One choice is a contraction of "they are," which also adds an extra verb and uses a plural subject.
The only option that is a singular possessive pronoun correctly referring to "a robotic swarm" and showing ownership of the movements is A) its.