<p>Of all the meteor showers observed over the past two centuries, [[they have not observed one to produce]] a body that survived passage through Earth's atmosphere.</p>
<p>(A) they have not observed one to produce
(B) they have observed not one producing
(C) not one have they observed producing
(D) not one has been observed to produce
(E) there has been not one observed to produce</p>
<p>I had to choose between D and E, and D was the correct answer. However, I still wanted to know why E is wrong. Collegeboard offers:</p>
<p>"Choice (E) involves an error in pronoun reference. The expletive pronoun "there" has no antecedent to which it refers."</p>
<p>Can someone please explain to me what exactly this means?</p>
<p>I think they mean that because it’s an expletive pronoun, it has no antecedent and the sentence would be clearer without it. “Of all…not one” is a common construction, anyway.</p>
<p>Remember that even if you can’t identify the exact problem with an answer choice, if it sounds awkward and all wrong…it is wrong.</p>
<p>After the comma, you need to have the noun that is being referred to, since the first part is a dependent clause. The “there,” as it’s not the same subject (i.e. the meteor showers - “not one” refers to "not one meteor shower) as in the first half of the sentence, it is incorrect.</p>