Now seen as a mechanical precursor to the e-reader, Spanish educator and inventor Angela Ruiz Robles's Enciclopedia Mecanica eschewed pages in favor of three horizontal paper scrolls that could be easily swapped out to accommodate a range of subjects. Though Ruiz Robles's prototype had limited functionality, interactive features described in her 1949 patent—such as a button labeled "verb" that would illuminate relevant text when pressed—_____ an impressive early vision of hypertext.
Which choice completes the text so that it conforms to the conventions of Standard English?
Explanation
Context: The subject of the sentence is "interactive features described in her 1949 patent," an interrupting example follows it, and the blank must supply the clause's main verb before "an impressive early vision of hypertext."
Answer: B) reveal
Why? The head of the subject is the plural "features," and the sentence delivers a present-tense assessment of the patent, so the plural present verb "reveal" is what agrees.
Traps:
- A) "revealing" is a participle, which would leave the sentence with no main verb at all.
- C) "reveals" is singular, agreeing with the nearby "patent" or "button" instead of with the actual subject, "features."
- D) "has revealed" pairs a singular auxiliary with a plural subject; agreement would require "have revealed."