GMAT Club World Cup 2022 (DAY 1): Once portrayed as the engine of a

Manhattan Prep Official Explanation:

First Glance: Differences in the answer choices provide clues about what a problem might be testing. Before reading the sentence, glance at the beginning of the underline and down the beginning (just the beginning!) of the five answer choices to look for one early clue as to what this sentence is testing. In this case, the first glance suggests structure/opening modifier issues: Two answers begin with the noun modifier Once portrayed, and the other three start with a connector word (While, Although, With).

Issues:

(1) Modifier

The original sentence begins with the noun modifier Once portrayed, but the modifier itself does not indicate what it is referring to. What was portrayed as the engine of a future golden age? The answer to this question must be the main noun or subject after the comma. In this case, the most logical answer to the question is artificial intelligence technologies. Answers (A) and (E) illogically use the rapid advancement as the main noun after the comma, so eliminate (A) and (E). Answers (B), (C), and (D) all already contain a subject, so they depend less on what comes after the comma. That said, the With at the beginning of answer (D) doesn’t do as good a job of signaling a contrast as While or Although, creating a potential meaning issue.

(2) Parallelism/Meaning

The inclusion of and in the underlined portion and the variety of options after it (and, and to, and has) provide a strong indication that parallelism is being tested. The parallel structure for each answer is laid out below, with the root phrase at the top and the parallel branches listed below:

(A) …the rapid advancement … has led to questions about…

○ …the nature of work
○ …the rights of machines
○ …revised definitions of life itself

● This last part is problematic, as it implies that the rapid advancement of AI has led to questions about revised definitions. It would make more sense to say that the advancement of AI has led to revised definitions of life itself rather than to questions about those revised definitions. Check the other options; since they do offer a more logical meaning, eliminate (A).

(B) …their rapid advancement has led…

○ …to questions about…

■ …the nature of work
■ …the rights of machines
○ …to revised definitions of life itself

● This parallel structure is correct (though complicated, because it splits the words out into two separate parallel structures rather than one list of three items).

(C) …the rapid advancement … has led to questions about…

○ …the nature of work
○ …the rights of machines
○ …has revised definitions of life itself

● The last part of the parallel structure doesn’t follow well from the root phrase (has led to questions about has revised definitions…). In addition, it starts with a verb, while the other two parts of the list are nouns. Eliminate (C).

(D) …their rapid advancement…

○ …has led to questions about…

■ …the nature of work
■ …the rights of machines
○ …has revised definitions of life itself

● In this case, while the parallel structure is grammatically correct, the last part contains a meaning issue. It illogically implies that the rapid advancement has itself revised definitions of life. People would revise such definitions based on the technology; the rapid advancement itself cannot actively revise anything. Eliminate (D).

(E) …the rapid advancement … has led…

○ …to questions about…

■ …the nature of work
■ …the rights of machines
○ …to revised definitions of life itself

● This parallel structure is correct (though complicated, because it splits the words out into two separate parallel structures rather than one list of three items).

(3) Pronoun

Pronouns appear in answer choices (B), (C), and (D). In (B) and (D), the pronoun their refers to artificial intelligence technologies. While the pronoun is technically ambiguous (as it could also refer to the plural noun robot assistants), the GMAT frequently lets such cases of ambiguity slide, especially when the pronoun in question is used in a way that parallels the usage of its antecedent. In (B) and (D), because artificial intelligence technologies is at the beginning of the first part of the sentence and the pronoun their is at the beginning of the second part of the sentence, the GMAT’s take is that the pronoun refers to its antecedent in a way that’s clear enough.

The pronoun it in answer (C) is problematic, though. As a result of the same logic outlined in the prior paragraph, it must refer to the rapid advancement, which is the subject of the second clause in the sentence. However, the rapid advancement doesn’t make sense as the subject of the first clause—it’s not the advancement that was portrayed as the engine of a future golden age but rather the technologies themselves, and the singular pronoun it can’t refer to the plural noun technologies. Eliminate (C).

The Correct Answer: Answer (B)’s opening modifier tells you what subject it is discussing, so that subject does not need to be repeated after the comma. The parallel structure is grammatically correct and conveys a logical meaning for every part of the sentence.

OA: B