<p>From their study of the stars, ancient mariners could navigate confidently without dependence upon the hi-tech devices in use today. No error</p>
<p>In sentence above, I chose "study" as incorrect because I thought it apparently has to be "studies" as subject pronoun is plural "their"</p>
<p>But answer says no error! ***?
Why is "study" allowed to be singular in this sentence?</p>
<p>The pronoun “their” is referring to “ancient mariners” - not “study”.</p>
<p>Ancient mariners are plural. Then how come “study” is remained as singular and not “studies”?</p>
<p>study is independent from Ancient Mariners. Making study plural would only change the meaning of the sentence. </p>
<p>Take this for example.</p>
<p>Ancient Mariners did a study on stars. — Grammatically correct, they did one study of the stars</p>
<p>Ancient Mariners did studies on the stars. - The only change here is in the meaning of the sentence. </p>
<p>For all SAT writing MC questions, always avoid changing the meaning of the sentence, unless there is no other option.</p>