Scientists who studied the famous gold field known as Serra Pelada con

enochjason



E has already that structure of omitting the preposition 'by' and is therefore wrong.
If you are using by after 'not', then you have to use 'by' compulsorily to keep //ism of correlative conjunction "not… but". You cannot, therefore, skip it. If there is no 'by' after 'not', then you can skip it after 'but'.

Hi my honorable expert,
I'm not sure how 2 'and' has been used among 3 nouns (i.e., jungle soils, rivers, and rocks) without using any punctuation?
Thanks__

Public Service Announcement: do not waste your time looking for mistakes in the non-underlined portion of the sentence! Unless, of course, they somehow cause a problem in the underlined portion.

I certainly understand why the construction looks strange to you - it's fairly unconventional usage to write A and B and C, rather than A, B, and C, but it isn't wrong. Remember that if we write "X and Y" we don't use a comma, so there's no reason why we absolutely have to use commas when we write X and Y and Z." The commas in a list are there to signal to the reader that one element has ended and the next has begun, but "and" performs the same function. Here, if they'd written "jungle soils, rivers, and rocks," it might seem as though the writer intended to convey, "jungle soils, [jungle] rivers, and [jungle] rocks," as opposed to "rivers" and "rocks" in general. The "ands" avoid that ambiguity.

But ultimately, if we don't have the option of changing a construction, there's no reason to worry about it.

I hope that helps!

If you understand that the concept being tested here is parallel structures and the correct idiom is ‘produced not by X but by Y’, we can arrive at the right option in a matter of seconds.

Let’s look at the options:

A: ‘but that’ is not parallel. Eliminate.

B. usage of ‘but’ and ‘instead’ is redundant. Also, does not maintain parallelism. Eliminate.

C. missing preposition ‘by’ and therefore not parallel. Eliminate.

D. Correct parallel structure: ‘produced not by the accepted methods… but by swarms of…’ This is the best choice.

E. Same as A. ‘But that’ is not parallel in structure. Eliminate.

Option D is the best option.

Hope this helps!

The only sentence that made sense was D.

Scientists who studied the famous gold field known as Serra Pelada concluded that the rich lode was not produced by the accepted methods of ore formation but that swarms of microbes over millions of years concentrated the gold from jungle soils and rivers and rocks.

I think the word "concluded" is modifying Pelada.

Can you pl. correct me if I'm wrong!

The structure of the sentence is:

Scientists who studied the famous gold field known as Serra Pelada concluded <something>

Notice that "who studied the famous gold field known as Serra Pelada" is a modifier, modifying "Scientists".

So, the "core" of the sentence (without the modifier) is:

Scientists concluded <something>.

Now, it is very clear that "concluded" is not really modifying anything; in fact, "concluded" is the main verb.

p.s. Our book EducationAisle Sentence Correction Nirvana discusses how to differentiate between Simple Past Tense and Past Participle, its application and examples in significant detail. If you or someone is interested, PM me your email-id; I can mail the corresponding section.

Hello adarsh618,

We hope this finds you well.

To provide a bit of clarity here, in this sentence "concluded" is not a modifier; it is an active verb acting upon the noun "Scientists".

We hope this helps.
All the best!
Experts' Global Team