<ol>
<li>[Among] American swimmers, Jason Lezak is an excellent example of an athlete who, [while contributing] to the success [of his] teammates, has brought attention to [himself]. [No error]</li>
</ol>
<p>I first thought the answer was B because while contributing and has brought attention to appear to be in different tenses. The book offers no reason for the answer not being B. Why is it E and not B?</p>
<ol>
<li>[Thanks] to the rapid growth of the internet, the internet service provider [gained] three million subscribers by 1996 and, by 1996, [was gaining] [as many as] a thousand new customers each week. [No error]</li>
</ol>
<p>I initially chose E because the sentence appeared to be grammatically flawless, but the book purported that it was B. It says: "Since both of the events (gained and was gaining) happened in the past, you need the past perfect tense, which uses the helping verb had. The sentence should read the internet service provider had gained three million subscribers."* Can someone please offer another explanation for this? I'm not sure why the past perfect tense is needed.</p>
<p>I showed the questions to my dad and he thought the answers were contradictory. Is he right or do we just need to be enlightened?</p>
<p>Thanks in advance.</p>
<p>*Am I legally allowed to post this? The text is taken directly from the book.</p>
<p>“contributing” is a non-finite verb, which means that is has no tense: it’s a participle, which serves as an adjective. “contributing” is, then, modifying “who,” which is a relative pronoun whose antecedent is “Jason Lezak.” The sentence could be rewritten as the following:</p>
<p>While contributing to the success of his teammates, Jason Lezak is an excellent example of an athlete who has brought attention to himself. whose form is</p>
<p>PR’s answer is correct, but the explanation is not. Even though both are past actions, “had gained” would be needed regardless of the tense of the other verb. “by” often signals the use of the past perfect (or, as we see here, the past continuous) because, for example, the gaining did not all take place in 1996; it accumulated prior to that. One does not, for further example, say, “By age six, I went to four birthday parties” (that would require “At” instead of “By”); he or she would say, “By age six, I had gone to four birthday parties.”</p>