<p>since there still seems to be some debate about this question:
Very subtle stuff, but I picked “to complete” as the error, because the phrase “to complete” has a different implicit subject than the one previously established in the sentence.</p>
<p>“Jerry agreed to perform”
is a correct sentence, because Jerry is the one doing the performing.</p>
<p>“The chunnel (blahblah correct stuff), and it took years to complete”
Seemed initially wrong to me, because the chunnel is not the one doing the completing. Obviously, people say this type of thing all the time, so I second guessed myself as to whether or not this was correct. What I found at [Infinitive</a> - Wikipedia, the free encyclopedia](<a href=“http://en.wikipedia.org/wiki/Infinitive]Infinitive”>Infinitive - Wikipedia) is that nothing is technically wrong with the sentence, since the infinitive follows “years,” the object of the sentence. It is technically an adverb phrase.</p>
<p>With that said, I think that “to be completed” is infinitely more stylistic, so I think this one is still open for debate.</p>
<p>Yeah, I don’t think the chunnel question is going to have a definitive answer until the scores are released. Though to be honest I don’t see how they could make the argument that “to complete” is necessarily incorrect.</p>
<p>the thing is whenever I’ve read/heard about any project, it’s always been “this took ___ years to complete”. It’s not an infitive per se… It’s almost a purpose clause (here’s where the latin helps) It took 15 years so that the chunnel might be completed = It took 15 years to complete the chunnel = it took 15 years to complete. syntax is different, meaning isn’t.</p>
<p>It’s some kind of adverbial infinite use, but if I was thinking in latin grammar (which helps more with english than you know), it reeks of a purpose clause</p>