Writing question

Test Preparation SAT Preparation
1

<p>Most major air pollutants cannot be seen, although large amounts (of them) (concentrated in) cities (are visible) (as) smog. (No error)</p>

<p>The answer is E.</p>

<p>I choose "are visible" as the error because I thought the sentence needed another "as" to complete the "as... as" construction.</p>

<p>Most major air pollutants cannot be seen, although large amounts of them concentrated in cities are AS visible AS smog. </p>

<p>When would the "as...as..." construction be necessary...? And when would it not? Because in this case it wasn't...</p>

2

<p>as…as is used when you are comparing two things. Seen AS smog is correct because the pollutants are not LIKE the smog, they ARE the smog. I guess for this sentence you would need to know what smog is.</p>