The Chicago and Calumet Rivers originally flowed into the

[tim]

are you saying the sentence doesn't make sense to you without the "but"? what makes you think the "but" is necessary?

[gmatalongthewatchtower]

are you saying the sentence doesn't make sense to you without the "but"? what makes you think the "but" is necessary?

In fact, why is "BUT" unnecessary? The meaning says that initially the river flowed through XYZ but now (...while typing I couldn't help to use "but" or "however") the river is following a different pattern because of the construction of canals. In fact, the original sentence has used "originally" and "now" modifiers. It seems to me that the intention of the sentence is to contrast. However, the OA thinks otherwise. I am not able to understand the reasoning behind OA.


Thanks

[jlucero]

Writing preferences will kill you on the GMAT. It's not how YOU would write the sentence, but what's wrong with writing it these other four ways.

The rivers did X but now they do Y.
The rivers, originally doing X, do Y.

Same meaning, just a different style of writing. Look for errors, not preferences.

[divineacclivity]

Ron,

You've beautifully explained the difference between the use of "adopting" and "adoption" in one of your "Thursdays with Ron" sessions taking the following question as an example:
"Thirteen states from all regions of the country announced ..."

In the later part of the video, you also explained why "construction" should be preferred over "constructing" taking another example:
"Chicago and Calumet Rivers originally flowed into ..."
but that video is not complete and I so want to listen to the remaining part as well.

Could you please share the link to remaining part of the video please? That'll be a lot of help.

thanks

[RonPurewal]

the only place where i'm aware of links to the videos is the "thursdays with ron" web page.
http://www.manhattangmat.com/thursdays-with-ron.cfm

there shouldn't be any links to incomplete videos there. are there links to incomplete recordings?
if so, please tell us which one(s) -- that would actually be a pretty big issue. thanks

[divineacclivity]

the only place where i'm aware of links to the videos is the "thursdays with ron" web page.
http://www.manhattangmat.com/thursdays-with-ron.cfm

there shouldn't be any links to incomplete videos there. are there links to incomplete recordings?
if so, please tell us which one(s) -- that would actually be a pretty big issue. thanks

Here's the youtube link: http://www.youtube.com/watch?v=gv94U6MG_8I

If you could please tell me how I'd know which video from your Thursdays' library to look into for this particular problem :(

[tim]

http://vimeo.com/37267206

this was not that hard. you can tell when your youtube link was posted, and this is the most recent Thursdays with Ron prior to that according to our website..

[divineacclivity]

http://vimeo.com/37267206

this was not that hard. you can tell when your youtube link was posted, and this is the most recent Thursdays with Ron prior to that according to our website..

Ah, ok. Thank you soooooooo much for all the help.

[tim]

:)

[ganpathi]

B. Rivers had originally flowed into the St. Lawrence by way of Lake Michigan, but they have been redirected by constructing
...
whats wrong with B..

there are two things wrong with (b).

one:
the use of the past perfect (had flowed) is inappropriate, because there is no second past-time marker or event to which this first event is relevant.
compare: the rivers had originally flowed into the st. lawrence, but then their course was diverted by...
the correct tense to use here would be the simple past, because this is the only past time frame referenced in the whole sentence.

two:
'by constructing' seems to refer back to the rivers as its ostensible subject, implying (absurdly) that the rivers themselves constructed the canals.

1) The Chicago and Calumet Rivers originally flowed into the St. Lawrence by way of Lake Michigan, but having been redirected by constructing canals so that the water now empties into the Mississippi by way of the Illinois River.

(A) Rivers originally flowed into the St. Lawrence by way of Lake Michigan, but having been redirected by constructing
(B) Rivers had originally flowed into the St. Lawrence by way of Lake Michigan, but they have been redirected by constructing
(C) Rivers, which originally flowed into the St. Lawrence by way of Lake Michigan but have been redirected by the construction of
(D) Rivers, originally flowing into the St. Lawrence by way of Lake Michigan, but having been redirected by the construction of
(E) Rivers, originally flowing into the St. Lawrence by way of Lake Michigan, have been redirected through the construction of

OA: E
2) Ozone, a special form of oxygen that screens out harmful ultraviolet rays, reaches high concentrations twelve miles above Earth, where it has long appeared that it was immune from human influence; we have now realized, though, that emissions of industrial chlorofluorocarbons deplete the ozone layer.

(A) has long appeared that it was immune from
(B) has long appeared to have been immune from
(C) has long appeared as being immune to
(D) had long appeared immune to
(E) had long appeared that it was immune to

OA: D

Hi,
The above questions are from GMATPREP and have been discussed at length in this forum. I still have a doubt though.

The OA to question 1 is E and not B because choice B has an action (Rivers had originally flowed) in the past perfect tense followed by another in the present perfect. There is no action in the simple past to fill the time gap between the past perfect action and the present perfect action.
However, the OA to question 2 is not supported by the above explanation. The action (had long appeared immune to) in the OA is in past perfect tense followed by another in the present perfect (we have now realized). There seems to be a "˜gap’ between the two actions. This was the reason for eliminating choice B in question 1.

My understanding of usage of tenses is:
Past perfect + simple past + simple present/present perfect - ok.
Past perfect + simple present/present perfect - not ok. The action in past perfect tense in this construction should be expressed in the simple past.

Why should we eliminate B for question 1 but choose D for question 2. Seek your clarification in understanding the OAs please.
Thanks,

[tim]

apparently the GMAT is okay with that construction if they accepted it in 2. the real reason B is wrong in 1 is because "by constructing" is not a valid prepositional phrase..

[divineacclivity]

apparently the GMAT is okay with that construction if they accepted it in 2. the real reason B is wrong in 1 is because "by constructing" is not a valid prepositional phrase..

Tim, why's that so?
Isn't the following a similar construction & a correct one:

Molly won the debate in her school by speaking effectively on stage.

Please explain. thanks in advance

[tim]

what makes you think this is correct? have you ever seen it used correctly in a GMAT problem? remember, you are wasting your time if you make up your own sentences and ask if they're correct. instead, you should focus on actual constructions that have actually shown up on the GMAT..

[divineacclivity]

Really? Is "by speaking" incorrect in the following sentence?
Molly won the debate in her school by speaking effectively on stage.

I may be wrong & please correct if I'm wrong but it sounds a little shocking because I always thought such a usage - "by speaking" e.g. in the sentence above, is correct.
I don't remember specifically seeing such a usage on gmat or even heard someone objecting to it until now. It is hard to assume that all that I know/believe but haven't seen on gmat is wrong because I've seen very little of gmat as yet & I'm still learning keenly :)

Secondly, No offense meant but I made up a sentence of my own just to take an example to understand the rule better and it'd be almost impossible to find a gmat question that talks exactly about the rule I want to understand. I might've made a very flawed sentence unknowingly & I'd be grateful if you or other experts help me learn by pointing out the flaws. I do try n remember the rules I learn from the experts like you.

So, pls help me understand if "by constructing" is always wrong or is it wrong just because "by constructing" seems to be the work/action of the subject i.e. "Rivers". thanks in advance

[tim]

no offense taken; you did nothing wrong as such. i'm just trying to help you allocate your study time effectively. if you make up your own example but cannot relate the issue directly back to a GMAT problem, you may be studying something that doesn't need to be studied. in other words, i'm not saying that your sentence is right OR wrong, only that without evidence that this issue is relevant there is no reason to care one way or the other..