By pressing a tiny amount of nitrogen between two diamonds

[RonPurewal]

If you interpret that sentence as "___, but ____", then the parallelism is fine.

E.g.,
Matt is not a writer, but he is an editor.
If you interpret this as "not ___ but ___", then it doesn't work. ("Not" is followed by a noun, while "but" is followed by an entire sentence.)
On the other hand, if you interpret it as (sentence) + but + (sentence), then it's fine.

Same here.

[RonPurewal]

"Are" is also necessary in that sentence because of "simply".
"Simply" is an adverb that describes the fact that these things are random byproducts; i.e., it describes the verb "are". If you remove "are", then "simply" is an orphan with nothing to describe.

[Haibara]

Ron, great explanation about the detection of "simply", which caution me to attend to details. But I guess that's difficult to detect in real test with short time, not to mention as a non-native speaker.

Paleontologist Stephen Jay Gould has argued that many biological traits are not the products of natural selection, because they enhance reproduction or survival, but are simply random by-products of other evolutionary developments.

The part following "but" is not a sentence, so
should I attribute it to the "__, but___" structure or the "not___, but ___" structure?

Also, do you mean that the sentence is correct as long as one of the two interpretations(or structures) makes sense, supposing no other grammatical or meaning errors exist?

Thanks very much!

[thanghnvn]

yes, it is.
[editor: see the long post below for a much more complete treatment of this idiom.]

keep in mind for future questions that it IS acceptable to phrase the expression that way!

however, it seems that there is a question in og10 or og 11, in which we have to choose between "keep but" and "omit but". This means keeping "but" is prefered not required ?

why gmat play this game?

[RonPurewal]

Also, do you mean that the sentence is correct as long as one of the two interpretations(or structures) makes sense, supposing no other grammatical or meaning errors exist?

Thanks very much!

Yes.

[RonPurewal]

The part following "but" is not a sentence, so
should I attribute it to the "__, but___" structure or the "not___, but ___" structure?

I don't understand the question. What is the significance of "it's not a sentence"?

The "not ___ but ___" structure is not viable here (as already discussed), so you have your answer.

[RonPurewal]

however, it seems that there is a question in og10 or og 11, in which we have to choose between "keep but" and "omit but". This means keeping "but" is prefered not required ?

Edition and problem number, please. Thanks.

[zeal4mba]

Thank you very much Ron. I never knew this concept!

[RonPurewal]

Sure.

[FanPurewal]

ron, are you sure you are not an accurate computer? or digital something else??

amazing explanation!!

[jnelson0612]

ron, are you sure you are not an accurate computer? or digital something else??

amazing explanation!!

Ron is a cyborg. That explains all of this. :-)

[sahilk47]

Crystal clear post !.

But I have a small clarification in the example you provided.

the small child was relieved to hear that the rustling under the bed was caused not by a ghost but by his pet cat.


Are the parts high lighted parallel?
We have

by a ghost --> By + object
by his pet cat-->By + pronoun +object.

So when the right most part gets locked in, the pronoun also gets locked so should the left part must also have a pronoun right?

no. if anything were this strict, it would basically be impossible to write anything with descriptive language.

basically, as long as 2 parallel structures have the same basic form / grammatical role -- irrespective of add-ons like modifiers -- they're legitimately parallel structures.

e.g.

i have a truck and a bicycle.
--> parallel

i have a big, red, rusty old truck, which has been driven over 250,000 miles, and a bicycle.
--> still parallel.

Hi Ron

I was going through this entire thread and I had a small doubt. In the second example above, why didn't you put and between red and rusty ? Is it not necessary there ?

Thank you

[NL]

Wow! That's a deep dive, Ron!…. Brilliant analysis about the most important "finger" for making decision in similar cases!

Seeing this example…..

Matt is not a writer, but he is an editor.

…… I wonder whether the two structures "not… but" and "not only…. but also" have different meanings, but a common thing, which is a parallel form?

[RonPurewal]

they have totally different meanings. if you are not only a writer but also an editor, then you are BOTH a writer and an editor.

[ysyanshi]

"Are" is also necessary in that sentence because of "simply".
"Simply" is an adverb that describes the fact that these things are random byproducts; i.e., it describes the verb "are". If you remove "are", then "simply" is an orphan with nothing to describe.

Hi Ron, thank you for the fine explanation! But if "are" here is necessary because "are" is the word that "simply" wants to describe, then how about another sentence from GMATPrep:

"Introduced by Italian merchants resident in London during the sixteenth century, life insurance in England remained until the end of the seventeenth century a specialized contract between individual underwriters and their clients, typically ship owners, overseas merchants, or professional moneylenders."

I understand "typically" here does not modify NOUN, it is supposed to modify something like "being" which is omitted. Then Why here "being" can be omitted, but "are" in the sentence of the question is necessary?