The application of a new method for analyzing the chemistry of tooth enamel allows scientists to examine molars of prehuman ancestors and determining that their diets were more varied than had been supposed.

(A) The application of a new method for analyzing the chemistry of tooth enamel allows scientists to examine molars of prehuman ancestors and determining
(B) Through the application of a new method for analyzing the chemistry of tooth enamel, the molars of prehuman ancestors were examined by scientists who determined
(C) When they applied a new method for analyzing the chemistry of tooth enamel, scientists examined molars of prehuman ancestors, determining
(D) Applying a new method for analyzing the chemistry of tooth enamel, the molars of prehuman ancestors have been examined by scientists, who determined
(E) Applying a new method for analyzing the chemistry of tooth enamel, scientists have examined molars of prehuman ancestors and determined


The OA is E.
I chose C.
My question is:
1. I don't know what's wrong with C
2. The structure in E "scientists have examined molars of prehuman ancestors and determined" make me confused.
Is "determined" a past tense or a present perfect here?
If it is a present perfect, that means "have" can be omitted after "and".
If it is a past tense, it seems the tense of connection link between the preceding and the following is not so good, since "scientists have examined" first, then "determined".

hi -- is this problem actually from the GMAT PREP software?

if so, please post a screenshot to prove that the problem is from that software. sorry for the inconvenience.

if no screenshot is posted, we'll have to take down the thread in a week or two.

thanks

_________________
Being well-dressed gives a feeling of inward tranquillity [that] religion is powerless to bestow.
C.F. Forbes

OK, but I don't know how to upload an image. Is there any tutorial can follow?

http://s9.postimage.org/kmr8k47a5/SCPrep_Question.png

Hi Ron, I have uploaded.

thanks for posting the image.

choice (c) is tough here, but here are some things:

* the simple past tense is not ideal. the sentence is describing the results of a new analytical method, so, presumably, those results have some sort of immediate application to / impact on the present state of knowledge. the present perfect is the tense that is used to express this sort of relationship.
moreover, in choice (c), there is an undesirable parallelism between the different verbs in the past tense: "applied/examined" is in the same tense as "were more varied". since these verbs appear the same tense, the unintentional suggestion in the sentence is that we are talking about the diets of pre-human ancestors at the same time as the analysis described. that's not good.
in the correct answer, the difference in tenses -- the present perfect for the analysis vs. the simple past for historical statements about the diet of prehuman ancestors -- properly suggests the difference in time frames.

* the setup of the modifier -- "When they xxxx, they zzzz" -- doesn't really work here either. normally, this construction suggests that "zzzzz" is something that the scientists found while they were doing xxxx (a larger-scale effort), or as a result of doing xxxx.
for instance,
when i played a concert in france, i received unexpected jeers from some fans --> the second clause happened during the first one
when the detectives analyzed the DNA evidence, they discovered that the suspect was in fact innocent --> the second clause is a result of the first one
neither of these applies here. you want a modifier construction that given the idea that the "new method" describes the way in which the scientists made the determinations described. in other words, it's not a temporal relationship (as suggested by the word "when"); it's a modifier/descriptive relationship. choice (e), with its initial modifier, does this perfectly.




yep, it's a present perfect. there's no need to repeat the "have", as it applies to both parts of the construction.
i have been there and done that --> same sort of thing in this construction (which is also correct).

_________________
Being well-dressed gives a feeling of inward tranquillity [that] religion is powerless to bestow.
C.F. Forbes

WOW great explanation Ron - I have one another view about "WHEN" - Taking things literally When signifies a moment right? For example : When I spoke the words ,she was happy - implies jus a moment not a period of time correct!?

there's no reason to make this distinction. it could be either, depending on context.
when a substance reaches its flash point, it will burst into flames --> this is a particular moment
when you drive through the mountains, you should be especially careful not to speed --> this is the whole duration of your drive through the mountains

in any particular context it should be obvious which of these applies, so there's no point in trying to memorize a "rule" for this.

_________________
Being well-dressed gives a feeling of inward tranquillity [that] religion is powerless to bestow.
C.F. Forbes

Many thanks for your response.

sure.

_________________
Being well-dressed gives a feeling of inward tranquillity [that] religion is powerless to bestow.
C.F. Forbes

Ron, wonderful explanation of choice C wrongness. I wish you confirm some of my idea.

in E, correct answer, "applying" shows how the main action is perform. In C, "applying" show when and why the main action is performed.

I think of 2 patterns

DOING PHRASE+COMMA+MAIN CLAUSE
this pattern show that the action of doing starts before the action of main clause dose, regarding time. IS IT RIGHT?
The action of doing shows the method the main action is done. Is there any other semantic relationship between action of doing and that of main clause?

MAIN CLAUSE+COMMA+DOING PHRASE.
this pattern shows that the action of main clause starts before the action of doing dose. Is it right?

and, as you said to us many time, the action of the doing is result of the action of main clause. Is there any other semantic relationship between the action of doing and that of main clause?

semantic relationship between 2 verbs is tested frequently on gmatprep and I fee it hard. Do have any suggestion for studying it. any book or material you write on this? Dose manhantan company develop any chapter on this for us to learn the semantic relation more systematicly and so more effectively.

I don't think you can draw any conclusions about the timing of the two actions based on their relative placement in the sentence in your examples..

_________________
Tim Sanders
Manhattan GMAT Instructor

Ron, Thank you for your explanation of C. I repeat your idea.

donging comma+ main clause

in the structure, doing dose not bear the time relation but the modifier relation, doing shows how the main verb is done and what effect the main verb cause. in short, doing bear "how" relation and "causal" relation.

I have a question. I see 2 patterns:

doing +comma+main clause
and
main clause+comma+doing

what is difference between the two construction. I see an unofficial SC problem in which two patterns is tested. I never see gmat test the difference between these constructions. if you think that it is not neccessary to know the difference, pls, advise us

I think the instructors can explain better but my understandings are

Verbing + comma + main clause most of the time Verbing acts an adjective for example

Riding the bike through the forest, Ron reached home in 20 mins
here Riding is used as an adjective modifying the noun " Ron "



Main clause + comma + verbing most of the time verbing is adverbial modifier used to describe 1/ the complete action of the previous clause 2/ Should make sense with the subject of the previous clause 3/ Verbing should be a consequence of the main action of the main clause

For example...
Meryl Streep acted in the movie "The Iron lady", winning academy Award for Best Actress.

If you split this...

Meryl Streep acted in the movie "The Iron lady"
Meryl Streep won academy Award for Best Actress. (Winning becomes won = as winning takes the tense of the previous clause, simple past)

Also I think there are few example I have seen in which Verbing such as "resulting" "including" can't be used as adverbial modifier.. they are used to modify the previous noun..

I can't remember the example for "resulting" but i have seen one here in Manhattan forums
Example for including
Meryl Streep has won many awards including academy Award, Oscar, BAFTA and the like...
No comma before including!

I would wait for the Ron/Instructors to comment though!

Cheers

Example for + comma + , + resulting +

the-cottontail-rabbit-population-in-orange-county-t3012.html

Cheers

Ron, Manhantan experts,pls help.
I will make my question more simple.

in the pattern:

main clause+comma doing

"doing" shows

1/ How the main verb is performed, or
2/ effect of the main verb.

is there any other meaning that the "doing" show? pls, comment or supplement