Who would like to help with analyzing this sentence by grammar?

Question

Here is the sentence.
"What makes the Septuagint extremely invaluable is that the text from which it is translated has been lost."
So what does "it" refer to ?
"Which" usually is followed by a clause,why not here?
Thank you,

Answer 1

"It" refers to "the Septuagint".

"Which" IS followed by a clause: "it is translated". Here "which" is not the suject of the clause, but the object of the prepostion "from"--another way to write that part of the sentence would be:

The Septuagint (or it) is translated from a text which has been lost.

Does that look better to you? Both are perfectly grammatical but the one I wrote is less convoluted (of course it's also not the whole sentence) and probably more common.

Answer 2

"it" stands for the Septuagint.
as for which, it is not followed by a clause here, becase it is "from which". when relative pronouns are followed by a preposition, they don't take clauses.