<ol>
<li>(This holiday season), several members of the committee (are) sponsoring a dinner to raise money for their (efforts) to encourage (responsible) driving.</li>
</ol>
<p>I answered B for 'are' because it should be future tense? But it was E.</p>
<ol>
<li>(When teaching) high school students, (one) must not only command respect but (one should) develop rapport (as well).</li>
</ol>
<p>I answered C for 'one should' for redundancy, but it was E.</p>
<ol>
<li>Since the experiments began, the scientists (have discovered) that (they) can separate the reagents more effectively (by using) a centrifuge machine (and not) by shaking the tubes.</li>
</ol>
<p>I couldn't confidently find an error so I answered D for "and not" (no comparison terms).</p>
<ol>
<li><p>“This holiday season” is close enough to the present that the present tense can be used.</p></li>
<li><p>I would take out the second “one should,” too. I agree with your answer (C), so I think it is a bad practice question.</p></li>
<li><p>D is correct (“and not”) because the “more” in the sentence should be followed by “than” (the structure is “more . . . than”): they can separate the reagants more effectively by doing X than by doing Y.</p></li>
</ol>
<p>Thanks, #3 was B (in the book) btw and their justification was that they is ambiguous, but the verbs in the sentence imply voluntary action, so it couldn’t refer to the experiments.</p>
<p>In my opinion, the book is correct(first two questions):</p>
<p>1)When you are making a prediction or a plan(near time), you can use Present.
EX: My aunt arrives at 2 Oclock.(correct)
My plane leaves tomorrow.</p>
<p>2)Your answer is correct because (one) can be removed without affecting parallalism, but MC Graw’s answer is not wrong.</p>
<p>3)Your answer is correct(Doing my research on this question).</p>
<p>(2) is a mess. I think that “not only” needs to be paired with a “but also”, and that the “not only <phrase> but also <phrase>” clause needs to follow parallelism conventions. </phrase></phrase></p>
<p>So maybe:</p>
<p>When teaching high school students, one must not only command respect but also develop rapport.</p>
<p>It’s still awkward because of the use of “one”. The sentence needs to be rewritten.</p>