Usages of "as" and "although" with approximately the same meaning

Question

A. Huge boulders, far too big to be used as they were, were lying throughout the bed of the quarry.

and

B. Huge boulders, although they were far too big to be used, were lying throughout the bed of the quarry.

Would anyone please show me if, especially semantically, there is any difference between the two bold parts?

Thanks in advance.

UPDATED: For clarification I had to edit my question. My Prof. has just shown me the following is correct and means the same thing. WOULD The sentences A and B, therefore, mean the same thing, as well? if so,why? why not?

1.Although it may seem straightforward, the argument is indefensible.

2.Straightforward as it may seem, the argument is indefensible.

Answer 1

"as", and "although" aren't interchangeable. Consider the following:

although they were far too big to be used as they were

You can combine both and it still means the same thing. The core statement is "they were far to big to be used", and I can add the word although to say that there's something wrong with them, and I can add the phrase as they were to say "in their current state".

Let's do an experiment and apply my logic to your update:

Although it may seem as straightforward as it may seem...

Okay the repetition sounds quite strange, but the meaning has been preserved. The core idea you're trying to get across is 'it may seem straightforward', and you can use either (or both) although and as to get the same effect. Although goes at the beginning of the clause and as goes at the end.

Answer 2

Huge boulders, far too big to be used as they were, were lying throughout the bed of the quarry.

The bold part gives a reason of why the boulders were "lying" at the quarry. "As they were" means in that state of theirs. Hmm, sensible is this sentence and it can be used in a normal context.

Huge boulders, although they were far too big to be used, were lying throughout the bed of the quarry.

If it was me who attempted to write this sentence with an "although", I would have omitted "they were" and changed the sentence to

Huge boulders, although far too big to be used, were lying throughout the bed of the quarry.

Anyway, that's not the point here. The point is, you have possibly misunderstood their meanings. "Although" is used to demonstrate contrasts. I as the listener would expect to see something like this after the phrase with "although":

Although they were far too big to be used, workers wasted a dear amount of precious time trying to make them work.

There's no way "as" will be used to show contrasts the way this context is written. And reputable grammar sites or dictionaries can teach you almost all of the usages "as" can have.

Answer 3

In your example sentence "as" is a function word for comparison. "although" expresses contrast, opposion. Both ideas make sense but they are different ideas.

Answer 4

These sentences have one thing in common: their full meaning includes a "but" or "however", even though the sentences haven't been constructed to use those words directly.

Here's how I might paraphrase the first pair of sentences:

Huge boulders were lying throughout the bed of the quarry, but they were far too big to be used.

and the second:

The argument may seem straightforward, but it is indefensible.

I'm not exactly sure what you mean by a semantic difference between the two bold parts, but there are many ways these two sentences can be reworded. One way is to put the second part of the sentence first. In the first case, that can be done rather easily using although. Remember, although works like however, but although often works better when you are introducing the "however" part first, like this:

Although they were far too big to be used, huge boulders were lyaing throughout the quarry bed.

The second sentence is a bit trickier, because of the "may seem" part:

Although it is indefensible, the argument may seem straigtforward.

This does not work very well, because of the "may seem" part. The construct:

Although X, Y

works fine, but:

Although X, maybe Y

can sound rather odd.

That leads us to your last pair of sentences:

1. Although it may seem straightforward, the argument is indefensible.

2. Straightforward as it may seem, the argument is indefensible.

Both of these essentially mean:

The argument is indefensible, even though it might appear to be straightforward.

Answer 5

When as means although, it takes some set pattern:

adjective/adverb + as + clause

d. Cold as/though it was, we went out. ( = Although it was cold, we went out)

e. Tired as/though I was, I went on working.

f. Bravely as/though they fought, they had no chance of winning.

Note that as in those structures can also mean because. The context will tell you if as means because or although.

Tired as she was, I decided not to disturb her. ( = I decided not to disturb her, because she was tired)

In AmE as...as is normally used in this structure.

As cold as it was, we went out.

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From Advanced Learner's Dictionary -

As

(conjunction) in the way in which

Example

They did as I had asked.

Leave the papers as they are.

Your sentence #A

Huge boulders, far too big to be used as they were, were lying throughout the bed of the quarry.

Here they were means they appear or their appearance

So this sentence means Huge boulders were lying throughout the bed of the quarry. Those huge boulders are far too big, and not suitable to be used in the way in which they appear.

Your sentence #2

Straightforward as it may seem, the argument is indefensible.

Straightforward as it may seem follows the same pattern adjective/adverb + as + clause

And so here as means although. This sentence means Although it may seem straightforward, the argument is indefensible.

I believe you have no problem understanding sentence #1 and sentence #B.