Aside the fact that the big boss always prefers rather than over instead of, beyond GMAT too I will rather not like to use expressions such as opposed to and as against in issues of comparison. In my opinion and as per custom, you can use as against or as opposed to when you are opposed to or against something materially or conceptually. The element of dislike or repudiation should be innate in such contexts. For example, when I say that I am opposed to smoking either within office or in the public or when state that I am against public display of affection, I am meaning to say that I just don’t like them. But you can not use the same expressions to say tha admission in business schools this year has been nearly 150 thousand as opposed to or as against 100 thousands last year as if the relevant years are fighting between themselves. In these cases. proper diction requires to say that admission in business schools has been nearly 150 thousand this year in comparison to ( or as compared to or in contrast to blah, blah )100 thousand last year. Have I made my point?
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this is not a prallelism question. this is purely a meaning based question.

option A misses out the preposition at, which is necessary to describe where the bonding is affected. ‘is effected continuously over a broad surface rather than (at) a series of regularly spaced points with no bonding in between’. We need something to pin point a location which can only be done by ‘over’, ‘on’, ‘in’ and ‘at’.

'and hence the bonding, is a non-essential modifier in the midddle.

In metalwork one advantage of adhesive-bonding over spot-welding is that the contact, [strike]and hence the bonding,[/strike] is effected continuously over a broad surface instead of a series of regularly spaced points with no bonding in between.

In metalwork one advantage of adhesive-bonding over spot-welding is that the contact, and hence the bonding, is effected continuously over a broad surface instead of a series of regularly spaced points with no bonding in between.

instead of --used for replacement
I want coffe instead of tea .
rather than -- used to preference.



A)
= ...advantage of X over Y is that the contact.. is effected continously "over a broad surface" (O) instead of
"a series of regulary spaced points..." (S)
O and S are not parallel. also "instead of" is incorrec here.

D) ...advantage of X over Y is that the contact.. is effected continously "over a broad surface" (O) rather than
"at a series of regulary spaced points..." (S)
O and S are ll... and also rather than makes sense here.

correct me if i am wrong

From the GMAT point of view, I think the important Idioms are: 'Instead of' and 'rather than'. The Idioms 'In contrast to' and 'As opposed to' are not as important as the former in GMAT. This distinction would have been unnecessary, but for the fact that meanings of 3 out of the 4 idioms above are fairly similar. So strictly from the GMAT POV, I would chose 'Rather than' if I knew for sure 'Instead of' is incorrect AC.

Taking the sentence out of the GMAT Context I would definitely prefer B - 'As opposed to' over 'Rather than at'.

If an expert can shed some light over the usage then it will be really helpfull.

One more reason that I think goes in favour of D is Parallelism.

Sentence:
In metalwork one advantage [strike]of adhesive-bonding over spot-welding[/strike] is that the contact[strike], and hence the bonding,[/strike] is effected continuously over a broad surface instead of a series [strike]of regularly spaced points with no bonding in between[/strike].

I have struck out all the Middle Men.
Now to maintain the Parallelism, the correct structure should be:
Phrase starting with Preposition < Idiom > Phrase starting with preposition.
Option A: Does not maintain the above structure as 'Instead of' is the preposition and hence the phrase does not start with a preposition
Option B: Same problem structure is not maintained because 'As opposed to' entirely is the idiom.
Option C: Same problem structure is not maintained because 'In contrast to' entirely is the idiom.
Option D: CORRECT - The structure is perfectly maintained as 'Rather Than' is the idiom and hence the next Phrase begins with the preposition 'At'

E is out "being"
B is awkward out
C - "in contrast with" is used to compare like things. It is inappropriate in this context
A - instead of cannot be used to compare clauses

D remains.

Moreover the comparison is

bonding is effected continuously over a broad surface rather than at a series of regularly spaced points

How to decide between instead of and rather than here??
I think the verb is effected makes it necessary to use rather than and not instead of.

Experts pls comment on that.

‘Instead of’ means ‘in the place of’. In contexts when we have a dilemma of choosing between one or the other 'rather than' is more befitting.

In metal work one advantage of adhesive-bonding over spot-welding is that the contact, and hence the bonding, is effected continuously over a broad surface in the place of a series of regularly spaced points with no bonding in between

We can see how 'rather than' fits in better. I have hardly seen 'instead of' being approved by GMAT in such circumstances.
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I think the point is:

The comparison of contact. Whether contact is continuous or at regularly spaced points. The meaning of the sentence is trying to point out contact done continuously is better than done regularly spaced.

For choices A, B, which sounds pretty reasonable at first glance, you reject them for not having at

Only D makes the meaning complete.

The sentence goes:
contact, blah blah blah, is effected continuously over a broad surface instead of a series
of regularly spaced points with no bonding

Compares contact effected continuously to a series of regularly spaced points. <--- This doesnt make any sense whether it is A, B or C.

Not sure if I am putting my point across correctly.

Yes, I agree with your view. I would just like to try to put it across a bit more clearly, if I can.

The comparison markers here are
X instead of Y
X rather than Y

The comparison is between the two processes by which "the contact is effected":

Process 1 (X): The contact is effected continuously over a broad surface.
Process 2 (Y): The contact is effected at a series of regularly spaced points with no bonding in between.

Hence the compared elements are continuously over a broad surface and at a series of regularly spaced points with no bonding in between.

Moreover, the usage of "instead of" is restricted to nouns only, whereas "rather than" is more versatile and can be used for comparing not just nouns, nut also other elements such as participles, phrases etc. Hence "rather than" is the correct choice here.

The correct answer is D, which takes care of both the above issues.

I will say it has meaning error , rather than any idiom error.

Here, bonding is affected over a surface, hence comparison should be using some form of on.
In other words, parallel structure should same form of word.

A. over a surface is not parallel with a series of
B. again same error as A
C. same error.
D. over is parallel with at, hence right.
E. wrong contrast, changes meaning

Instead of, as opposed to , in contrast with , these all idioms, their X n Y should be parallel

In metalwork one advantage of adhesive-bonding over spot-welding is that the contact, and hence the bonding, is effected continuously over a broad surface instead of a series of regularly spaced points with no bonding in between.

daagh sir,
I am not able to understand the structure of the highlighted portion of the sentence, could you please help me to understand that.

Thanks in advance.

Regards,
Tamal

"hence the bonding" is an appositive modifier of the contact since the bonding or adhesion is the effect of the contact. "hence" makes this point clear and we should take them as one unit rather than as two different phenomena.
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I got this answer wrong initially, but I'm trying hard to use GMATNinja 's theory of going literal to understand this better:

- instead of and rather than are preferred idioms
- amongst these two, here's how i got to the right answer:

In metalwork one advantage of adhesive-bonding over spot-welding is that the contact, and hence the bonding, is effected continuously over a broad surface instead of a series of regularly spaced points with no bonding in between.
--> Makes it look like the contacts are effected instead of the regularly spaced points. But the intent is to show the comparison at the points where the welding effects are seen, so needs a "at"


rather than at --> in option D fixes it

Kudos if you feel content with the reply

This question focuses mainly on the difference between "Instead of" vs "Rather than"
Instead of: It only takes noun as an object and can only put nouns in parallel.
Rather than: It can take either a noun or a clause as its object. It can put nouns, pronouns or entire actions in parallel.
Hence D is correct answer choice

OFFICIAL GMAT EXPLANATION

The corrected sentence must contrast an effect of spot-welding with an effect of adhesive-bonding. To do so logically and grammatically, it must describe the effects in parallel terms. When inserted into the sentence, D produces the parallel construction over a broad surface rather than at a series. Having no word such as over or at indicate location, choices A, B, and C fail to complete the parallel and so illogically draw a contrast between surface and series. In E, as against being is a wordy and unidiomatic way to establish the intended contrast. Choice D is best.