The imperiled pleasures of parsing Austen

How many of today's middle school students (or older students), I wonder, can properly parse the second sentence in the excerpt below?

(Quick background: "she" refers to Elizabeth; Jane is Elizabeth's sister; Elizabeth has been away from home; Longbourn is the name of Jane and Elizabeth's home; Jane is in love with Mr. Bingley).

(More background, plus spoiler alert: Mr. Darcy has recently proposed to Elizabeth and explained to her how he talked Mr. Bingley out of pursuing Jane).

It was not without an effort, meanwhile, that she could wait even for Longbourn, before she told her sister of Mr. Darcy's proposals. To know that she had the power of revealing what would so exceedingly astonish Jane, and must, at the same time, so highly gratify whatever of her own vanity she had not yet been able to reason away, was such a temptation to openness as nothing could have conquered but the state of indecision in which she remained as to the extent of what she should communicate; and her fear, if she once entered on the subject, of being hurried into repeating something of Bingley which might only grieve her sister farther.

Here's a pop quiz:

Part I: Grammar

What is the main verb of the italicized sentence?
What is the subject of that verb?
What is its object?
Write out the full subject of "could have conquered."

Part II: Comprehension 

What is Elizabeth tempted to do and why?
Which factors are deterring her from doing it?

Complicating this sentence are:

(1) the now-unconventional use of the comma, which separates the subject from the main verb
(2) the now-unconventional use of the semi-colon to separate noun phrases rather than verbal clauses
(3) the out-of-date use of "such … as" instead of "that" in marking a relative clause

and… last but not least:

(4) the multiple embedding in both subject and predicate, which I've marked off by brackets below:

To know [that she had the power of revealing what [would so exceedingly astonish Jane], and [must, [at the same time], so highly gratify [whatever of her own vanity she had not yet been able to reason away]], was such a temptation to openness as [nothing [could have conquered] but [the state of indecision [in which she remained as to the extent of what she should communicate]]; and [her fear, [if she once entered on the subject], of [being hurried into repeating [something of Bingley [which might only grieve her sister farther]]]]].

Despite the persistence of Pride and Prejudice in classroom curricula and recommended reading lists, how many of today's teachers are providing the direct instruction that many students need, at least at first, to comprehend fully such sentences as this one?

Here's one way one might go about guiding students towards comprehension.

First, start with a much simpler sentence that gives the general shape:

Knowing this thing was a temptation to openness that nothing but indecision and fear could have conquered.

Next:
-- replace the clausal subject –ing ending with the more old fashioned infinitive (“knowing” -> “to know”)
--flesh out a bit more the object of “know”
--replace the more modern relativize clause marker “that” (“a temptation that”) with the more old-fashioned “such…. as” (“such a temptation as”)
--extrapose the “but a state of indecision and her fear” away from “nothing” to the end of the sentence:

To know that she had the power of revealing this was such a temptation to openness as nothing could have conquered but a state of indecision and her fear.

Next:
--flesh out a bit the object of “reveal”
--add modifiers to “state of indecision” and “her fear”:

To know that she had the power of revealing what would astonish Jane and gratify herself was such a temptation to openness as nothing could have conquered but the state of indecision in which she remained, and her fear of being hurried into something.

Next:
--add qualifiers to “astonish” and "gratify"
--flesh out a bit more the object of “gratify”
--place a comma between the subject and the main verb:

To know that she had the power of revealing what would so exceedingly astonish Jane, and must, at the same time, gratify her own vanity, was such a temptation to openness as nothing could have conquered but the state of indecision in which she remained, and her fear of being hurried into something.

Finally:
--flesh out "her own vanity" with embedding and modifiers;
--add a modifier to "remained";
--place a conditional appositive after "her fear";
--change the comma before "her fear" to a semi-colon:

To know that she had the power of revealing what would so exceedingly astonish Jane, and must, at the same time, gratify whatever of her own vanity she had not yet been able to reason away, was such a temptation to openness as nothing could have conquered but the state of indecision in which she remained as to the extent of what she should communicate; and her fear, if she once entered on the subject, of being hurried into repeating something of Bingley which might only grieve her sister farther.

Perhaps I'd be surprised at the number of kids who could pass my pop quiz without help. But, in this age of student-centered discovery in the classroom and record-low levels of independent reading, particularly of pre-20th century literature, at home, I'm guessing that more students than ever are stymied by these wonderful 19th century sentences, and, caught up in a couple of vicious cycles, increasingly shut off from much of what makes the classics so much fun to read.