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<li>(Although the candidate promised both to cut taxes and improve services, he) failed to keep either of them after the election.
(A) Although the candidate promised both to cut taxes and improve services, he
(B) The candidate, having promised both to cut taxes and improve services,
(C) Although the candidate made promises both to cut taxes and improve services, he
(D) Having promised, first, to cut taxes and, second, to improve services, the candidate
(E) The candidates promises were both to cut taxes and improve services, he</li>
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<p>I really didn't even look for the right answer, because I'm not asking about it. I'm asking whether there is a parallelism mistake here. The "both to cut taxes and improve services", should "to cut taxes" and "improve services" be parallel?</p>
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<li>The condition known as laryngitis [usually causes] the vocal cords and surrounding tissue to swell, [thus] preventing the cords [to move] [freely]</li>
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<p>“both” is used as a conjunction. There isn’t a parallelism issue in the first clause of question (1). The second “to” is implied. But there is no real harm in repeating the “to”. Some may argue that the repetition is necessary in that it serves to better emphasize the independence of the two items.</p>
<p>The real problem with the sentence is that the antecedence of the pronoun “them” (in the second clause) is ambiguous or in fact missing. It is also ambiguous in (B) and (C).</p>
<p>The logical antecedent of “them” is a plural noun – i.e. promises. So both C and E are possibilities. We can eliminate E because it contains two independent clauses – i.e. it’s a run-on sentence.</p>
<p>C is the best choice. But it is a poor excuse for an English sentence. Instead of “either of them” the sentence requires “either promise”.</p>