<p>Farmers [who grow] major crops such as corn, rice and wheat, [aware] that new developments in agricultural production can result in millions of dollars in additional revenue, [switching to newer], [more efficient] technologies. No error </p>
<p>So I picked A- aware, because I thought it was supposed to be "are aware"? Why is that correct?</p>
<p>p.s. I understand why D is wrong. But I don't understand why A is correct</p>
<p>It’s a nonessential clause modifying farmers. Consider the sentence if I take out the essential clause:</p>
<p>Farmers, aware that new developments in agricultural production can result in millions of dollars in additional revenue, are switching to newer, more efficient technologies.</p>
<p>Farmers [modifying clause] ARE aware that new developments in agricultural production can result in millions of dollars in additional revenue, switching to newer, more efficient technologies.</p>
<p>“aware that new developments in agricultural production can result in millions of dollars in additional revenue” although it may sound awkward, is correct. Its only function is that of a modifier. Taking it out of the sentence you’d get the main idea and as such it needs a main verb.</p>
<p>I don’t know the specific rule, but a technique that helps me read around potentially distracting phrases is to enclose them in parentheses. When I read a sentence, I place parentheses around prepositional phrases and clauses set off by commas. Then just read around the parenthesis and see if I see an error, if not I look in the parenthesis.</p>
<p>@Dorkyelmo, I know “aware that new” sound wrong, but if I were you I would continue reading on in the sentence, and if anything else really pops out at me, then I select that error. Because the previous answer that I thought was wrong could actually be right, it’s just because I don’t know the rule, I think it’s wrong. So in summary: If you see another error, and you definitive know it’s wrong, then choose that answer.</p>
<p>Following up on post #3
Farmers are aware that new developments in agricultural production can result in millions of dollars in additional revenue, switching to newer, more efficient technologies.</p>
<p>The problem with this choice is that the phrase "switching … " is now dangling.</p>
<p>If you were to keep the choice “are aware” you would need to modify the sentence further, as for example:</p>
<p>Farmers are aware that new developments in agricultural production can result in millions of dollars in additional revenue, and they are therefore switching to newer, more efficient technologies.</p>
<p>But you aren’t expected to make more than one change.</p>