In North & Hillard, Ex 215, the following sentence:
There can be little doubt that the guides, whether through treachery or ignorance, were mainly responsible for the disaster.
is translated by the answer book as:
parum quidem dubitari potest quin huius cladis, seu proditione seu inscientia, auctores in primis fuerint duces.
Why deploy the future-perfect, fuerint ("they-will-have-been the creators of the disaster")?
The English requires "were....responsible"; for me, there is a credible case for:
- sunt ("they are the creators"), even though the disaster has already happened;
- erant, giving the English: "they were"; and, presumably, continue to be responsible;
- yet again: fuerunt ("they were"): a completed process, in the past, now finished.
Any thoughts on why fuerint is used?