I just encountered the following sentence in The Oxford Guide to Style (p. 161) and could not figure out its structure:
Since it⁽¹⁾ is being presented as a direct quotation it⁽²⁾ is treated as one, it⁽³⁾ being immaterial that the words are not in English.
Why can the the final instance of the pronoun it, the one labelled with a superscripted ‘(3)’, be inserted at the end?
The first two instances of it, those labelled (1) and (2), are clearly coreferential to the same earlier antecedent (whatever is being presented as a direct quotation), but what is the third instance of it referring to?
What is the grammatical structure of this sentence?
Can that third it be omitted and the sentence remain grammatical and unchanged in meaning?
The parenthetical participle clause
- it being immaterial that the words are not in English
is the result of Extraposition (with dummy it inserted) on the parenthetical participle clause
- that the words are not in English being immaterial
Extraposition is very common in English when the subject of a short verb phrase (like being immaterial) is long and syntactically complex (like that the words are not in English). It moves the heavy material to the end, where it’s easier to parse in a right-branching language like English, and leaves a harmless little one syllable marker that leads right into the auxiliary verb, which is what English prefers.
If you exaggerate these dimensions, you see how useful it is. Contrast
- That I had to stand in line for over an hour yesterday is too bad.
versus the extraposed version
- It’s too bad that I had to stand in line for over an hour yesterday.
Oh, and as for the two beings, the first is simply the progressive construction operating on the passive be presented, producing is being presented, a tensed main verb chain. The second one is a non-finite equivalent of a tensed subordinate clause. In this case, something like
- since it is immaterial that the words are not in English
with the same extraposed clause. Unlike the first, this being is not tensed, since it’s a participle.