<p>This question was the question of the day for collegeboard. </p>
<p>The gong, believed to have originated in Western Asia, reached China in the sixth century, where it continues to be used for a wide range of purposes, [including as] a military signal, a rhythmic accompaniment for vocal performance, and a ritual instrument.</p>
<p>including as is correct but I didn't really get the explanation. </p>
<p>And why cant it be "which include"? cause that is what I put.
Thanks!</p>
<p>That was a tough problem, but I think the reason why it is “including as” serves to label all the purposes a gong does… as a signal, as a accompaniment, as a instrument. The other choices seem correct, but in terms of grammar and fluidity[the intent was labeling what a gong can serve as], they are weaker than the original choice.</p>
<p>Try this. Simplify the sentence to its barest form. Do this in two steps:</p>
<p>(1) The gong is used for a wide range of purposes, [including as] a military signal, a rhythmic accompaniment for vocal performance, and a ritual instrument.</p>
<p>(2) The gong is used [as] a military signal.</p>
<p>Now for (2) would you ever think of dropping the “as”? If you did you’d get: The gong is used a military signal. Obviously not right. You need the preposition “as”.</p>
<p>The missing preposition is a very serious error. If we agree then your question is whether or not there is a second error. I don’t think that “which include” is right, but even if it made sense, the SAT is not looking for second best. It’s looking for the simplest possible correction, assuming one is needed. In this case none is needed.</p>