<p>29<br>
Venezuela devotes a higher percentage of its budget to education (than do) other large Latin American countries such as Mexico and Brazil. No error</p>
<p>why is "do" necessary?</p>
<p>The second verb in a comparison is often omitted, but it helps to clarify. If one were to omit “do,” the sentence could be interpreted as meaning that Venezuela devotes a higher percentage of its budget to education than to the other listed countries.</p>
<p>Most major air pollutants cannot be seen, although large amounts of them concentrated in cities (are visible) as smog. No error</p>
<p>Shouldn’t “as” be put in the middle of “are visible”?</p>
<p>^ There is no comparison.</p>
<p>We are comparing the pollutants TO smog… we are just saying that we see them AS smog. Let’s suppose we had the word ‘smoke’ instead of smog.</p>
<p>as visible as smoke? or visible as smoke?</p>
<p>The form in which we see these concentrated pollutants is smog.</p>
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<p>Edited for clarification.</p>
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<p>Oops. That’s what I meant.</p>