The nineteenth-century chemist Humphry Davy presented the results of

Can anyone please help me out with question. I am not getting it

Official Explanation:
The main objective of the sentence is to describe "Essay on Heat and Light" as Davy's presentation of his own experiments and to further explain that the essay served as both a critique of previous chemistry and a vision of anew kind of chemistry. The clearest, most effective form for providing this explanation of the essay's function is to make critique and vision both appositives of "Essay on Heat and LIght", and to present them in a parallel structure.

Makes sense, but not easy to spot in my view.

Hi,

I think you should first look at the structure of the sentence..

1) the underlined portion describes the BOOK " essay on heart and light", so the underlined portion should start with appositive modifier, which is generally used as a noun modifier..
so a present participle CRITIQUING is wrong here and ' a critique' is correct
critique means a detailed analysis of something

this should get you down to three choices : A, B and C

2) parallelism
'a critique' should be parallel with 'a vision'

so only A is left

hope it helps

I got the right answer because I found D&E wrong for reasons below. Is the use of 'critiquing' wrong here? I think A,B, and C starting with 'a critique' is right because it represents the essay mentioned but 'critiquing' also makes sense because it represents the actions he did through the essay. Please enlighten me here!

(D) forward~~ is wrong.
(E) his own envisioning of ~~ is wrong.

We could certainly follow the fixed portion with an adverbial modifier ("critiquing"), but the choices that do so aren't parallel: both D and E present a noun after "and." C does the same thing in reverse, starting with a noun and following up with "envisioning." That leaves A and B, the latter of which uses the terrible "his envisioning" in place of the simple "a vision."

ssyohee, you've identified the same problem in E that I just mentioned in C. However, there's nothing wrong with the usage "from X forward," as in D.

Hi Experts.. I have a query regarding the difference in the usage of ???and??? and ???as well as???. Could you please give an example for each to help understand when one is preferred over the other. Or you can point me towards a post, if any, about the correct usages of both.
For example, in this sentence for the correct answer choice A. Would replacing ???as well as??? with ???and??? distort the meaning of the sentence?

Thanks.

When we use "and", we're connecting like forms and giving equal importance to those two elements. For example:

Tim went to the mall to buy candy and video games for his toothless infant.

Here, the two things Tim buys for his baby, "candy" and "video games", are basically interchangeable, in the sense that you could switch their order in the sentence and the meaning is identical.

However, consider:

Tim went to the mall to buy candy as well as video games for his toothless infant.

Now, Tim is going to the mall primarily to buy candy, and the video games are of slightly lesser importance. That's fine. It just means that the emphasis has changed. There'd be no way to choose between the sentences in a vacuum, since we can't be asked to read Tim's demented little mind.

The same is true in this example. If (A) used "and" instead of "as well as" the meaning would have changed a little, but it certainly wouldn't be incorrect, which is why the GMAT wouldn't ask us to make this distinction.

That said, an example of an error would be:

Tim went to the mall to buy both candy as well as video games for his toothless infant.

Here, "both" suggests that the two elements are on equal footing, and "as well as" suggests that the second element is less important. That's confusing, and therefore a problem.

I hope that helps!

Dear GMATGuruNY MartyTargetTestPrep IanStewart VeritasPrepHailey AjiteshArun DmitryFarber GMATNinja GMATRockstar,

Why don't we need present perfect tense for SINCE in choice A.?
How can present perfect tense be implied without any verb?

The nineteenth-century chemist Humphry Davy presented the results of his early experiments in his "Essay on Heat and Light", a critique of all chemistry since Robert Boyle as well as a vision of a new chemistry that Davy hoped to found.

I don't understand what verb you think should appear here? The word "since" in this sentence is being used in the same way as it is in this one: "Since World War II, the GDP has gone up." There's no verb with the "since".

"Since" here means "Since the time of". Perhaps you're interpreting it to mean "because", but that's not the intended meaning in this case.

Dear IanStewart,

The example you gave above also includes present perfect tense (i.e. "HAS GONE UP")

Moreover, the below OA also includes present perfect tense:

A March 2000 Census Bureau survey showed that Mexico accounted for more than a quarter of all foreign-born residents of the United States, the largest share that any country HAS contributED since 1890, when about 30 percent of the country’s foreign-born population was from Germany.

So, why does this question not include present perfect tense?

I'm still not clear what verb you're asking about - the verb "presented"? It's not even in the same clause as the word "since"; there's no relationship between the two words in the sentence. "Since" describes "chemistry since Robert Boyle" here. It's not connected to the verb "present". The sentence could even use future tense, if Davy was going to present his paper at some future conference, say.

Dear IanStewart,

My confusion comes from the idea that when SINCE appears in the sentence, PRESENT PERFECT TENSE should also appear as well.

Superlatives:
the best, the worst, the greatest, the most, etc.
When since + NOUN PHRASE serves to refers to a superlative or to an entire group or category, often no verb is included.
Examples:
The company's product is THE BEST invention since sliced bread.
Economists expect THE WORST recession since the war.
The author discusses EVERY movie since 2000.
In the green constructions above, there is no verb, so the usage of the present perfect is not required.


Here, since Robert Boyle serves to refer to an entire category -- ALL chemistry -- so there is no verb.
As a result, the usage of the present perfect is not required.

There is no such rule (expect perhaps in a very limited case, when "since" takes the meaning "since the time of", and is followed by a subject-verb pair). "Since Bob will work on the spreadsheet, I don't have to" uses "since" with future tense, and is a perfectly grammatical sense.

That's basically just some vague writing that pushes the boundaries of what makes sense. It's short for something along the lines of "a critique of all chemistry that has been developed since the time of Robert Boyle."

Hi @gmatninja,@e-gmat,

Is "hoped to found" towards the end of the sentence correct? Isn't is hoped to find? If its already found, what's the point of using hope, as its already found. Can't it just be chemistry that Dave found?

Many thanks,
B

In this context, "found" isn't being used as the past tense of find. This sentence uses "found" in its other meaning of establishing or originating something.

Davy hoped his essay would form the foundation of a new chemistry that he wanted to establish -- he wasn't looking for some chemistry that he hoped to find under a rock somewhere.

I hope that helps a bit!