Geologists once thought that the molten rock known as lava

[gmatwork]

Thanks for the clarification, Tim. I am sorry to disagree with you about the tense issue. I think the issue here is that the two clauses are linked by 'but' and when we link clauses by 'and' , 'but' we do not need past perfect , we do with simple past (Strategy guide says). Also, I found in the guide that past perfect is used when earlier action has a bearing on the later action.

Please comment.

[jnelson0612]

Thanks for the clarification, Tim. I am sorry to disagree with you about the tense issue. I think the issue here is that the two clauses are linked by 'but' and when we link clauses by 'and' , 'but' we do not need past perfect , we do with simple past (Strategy guide says). Also, I found in the guide that past perfect is used when earlier action has a bearing on the later action.

Please comment.

Tim is making a great point about what "had been" really means. Consider this sentence:

"The house had been green before it was repainted blue."

This shows how "had been" works; it indicates that something or someone used to have some quality or status but now does not. Ask yourself whether that is really an accurate way to describe the lava in this sentence; was it an underground remnant only until the scientists came along? That meaning doesn't make sense.

To be clear, we should use simple tenses as much as possible; the GMAT prefers the use of the simple tense to the use of the complex tense. We should use the complex tense past perfect if we have two past events and we are going to distinguish which one happened earlier. Do not use past perfect if simple past will do just as well, and that is the case in this problem. About the parallelism issue, definitely check out the problem Tim referenced, #42 in the Official Guide, then let us know if you have further questions. Thanks!

[gmatwork]

thanks for the clarification.

[jnelson0612]

:-)

[davetzulin]

"you also shouldn't use "having X..." unless having X actually has a direct effect upon the action in the main clause." - Ron

this is a really great point i've never seen elsewhere.

so comma-ing rules are actually backwards when the -ing is having? because normally it is the -ing is a direct result of the main clause, not the other way around.

My examples:

i bought a cat, satisfying my need for a pet. normal comma+ing, where -ing is a direct consequence

i bought a cat, having satisfied my need for a pet. -wrong I think?

i bought a cat, having heard of a two-for-one sale - the main clause is the consequence of the having? this seems to make sense

having heard of a two-for-one sale, i bought a cat - this appears to be the same as the previous to me...

GMAT prep example,
Some patients ... may simply have received inadequate treatment, having been prescribed a drug as a dosage too low to be effective or having been taken off a drug too soon. <--correct

one of the staff said that in the GMAT prep example, having is "comma+ing" explains the manner in which the main clause occurred. That makes sense, but it kind of contradicts what i quoted from you.

[tim]

sounds like you have the right idea. let us know if you need any further help on this topic..

[gmatwork]

Having failed the exam 5 times already, M. was astonished when he received a passing mark.

In the above sentence - "having failed the exam....." - What tense is this modifier using - present perfect?

Past perfect form of the same modifier will be - "Having had failed the exam"???

When to use each form - "having failed" VS "having had failed"?

What is the difference in the two forms in terms of meaning?

A doubt about choice (c)

C says - was an underground remnant of Earth's earliest days, which sporadically erupted

"which modifier should be able to modify the noun right before the comma AND also the noun that comes before the essential modifier (that modifies that same noun)......so why can’t in this case we apply the same flexibility that is allowed for "which" modifer
(Remember the case of the OG problem - Emily Dickinson’s letters....(in that problem we learned an exception for the "usage of which modifier". Why can’t we apply the same rule here and consider which modifier to modify "underground remnant" instead of "earliest days"( of Earth’s earliest days is essential modifier modifying an underground remnant.)

So as far as I understand for "which" modifier rules goes as below - it modifies the most eligible noun that comes right before the comma. If the noun right before the comma does not make sense grammatically then and ONLY then will we look for the noun that comes before the essential modifier.

[tim]

"In the above sentence - "having failed the exam....." - What tense is this modifier using - present perfect?"

that's what i would say, but i can't really think of any situations where the tense of a modifier should be an issue as long as it makes sense..

"Past perfect form of the same modifier will be - "Having had failed the exam"???"

no, but i can't think of a way to turn this into past perfect. again, not something you need to worry about on the GMAT..

"When to use each form - "having failed" VS "having had failed"?"

you will NEVER use the second one..

as for your question about "which", "which" will modify the noun right before the comma, as long as that is the type of noun that "which" can modify. "which" CAN modify "days", but it CANNOT modify a person (remember that's what was going on with Emily Dickinson's letters)..

[s_ram86]

What is the reason to eliminate option "D".

Is it becasue of using "would" ?
or
Is it because of modifier error [by using "that"] ?

[tim]

both! nice job..

[sachin.w]

I don't really get the usage of would.
Please let me know the right usage of would on GMAT with examples.

would be an underground remnant of Earth's earliest days that sporadically erupted

Here, is 'that' modifying days?

So as far as I understand for "which" modifier rules goes as below - it modifies the most eligible noun that comes right before the comma. If the noun right before the comma does not make sense grammatically then and ONLY then will we look for the noun that comes before the essential modifier.

Does the above rule apply to 'that' as well?

Regards,
Sachin

[tim]

I don't really get the usage of would.
Please let me know the right usage of would on GMAT with examples.

no thanks. we're going to leave it to you to find some examples and then bring them to us if you want to discuss them..

would be an underground remnant of Earth's earliest days that sporadically erupted

Here, is 'that' modifying days?

or "remnant". i'd actually go with "remnant" because that's the interpretation that actually makes sense..

So as far as I understand for "which" modifier rules goes as below - it modifies the most eligible noun that comes right before the comma. If the noun right before the comma does not make sense grammatically then and ONLY then will we look for the noun that comes before the essential modifier.

Does the above rule apply to 'that' as well?

no it doesn't..

[alexcey]

I still wonder if choice C has enough errors to be considered incorrect on GMAT.

"molten rock known as lava was an underground remnant of Earth's earliest days, which sporadically erupted"

(C) This choice improperly uses the relative pronoun "which" to modify "Earth's earliest days" instead of "molten rock known as lava."

1. Grammatically, which can point to either "remnant" or "days", leaving us with to choices. Word "days" is closer, but "of Earth's earliest days" is a modifier for word "remnant." Both that and which often refer to the whole entirety versus the closest noun.

2. Semantically, phrase "which sporadically erupted" cannot modify "days" as the context makes it pretty clear that we are talking about lava as being "remnants of the earliest days".

3. Stylistically, it would have been clearer if "which" pointed directly to "molten rock known as lava", but no answer choice provides that option.

In addition I wanted to ask about the following. It seems that the majority of wrong GMAT SC sentences have at least two errors in them to avoid potential questioning of their incorrectness. Mid-level question usually have at least two grammatical errors, high level questions have one grammar and one meaning issue, and toughest ones are based on meaning issues completely. Is this observation valid in your experience?

[tim]

Both that and which often refer to the whole entirety versus the closest noun.

Prove it. Show us a GMAT question where "which" refers to anything other than the closest grammatically eligible noun. As near as we can tell, the GMAT is pretty strict regarding its use of "which". That said, your points 2 and 3 are irrelevant once we've determined that the choice is indeed grammatically correct..

As for your observation, I'd say there is a correlation there, but nothing significant enough to rely on with any certainty (or to care about for that matter)..

[alexcey]

Both that and which often refer to the whole entirety versus the closest noun.

Prove it. Show us a GMAT question where "which" refers to anything other than the closest grammatically eligible noun. As near as we can tell, the GMAT is pretty strict regarding its use of "which". That said, your points 2 and 3 are irrelevant once we've determined that the choice is indeed grammatically correct..

As for your observation, I'd say there is a correlation there, but nothing significant enough to rely on with any certainty (or to care about for that matter)..

Sure, here is an example from GmatPrep software:

142. To protect English manufacturers of woolen goods both against American and Irish competition, England passed the Woolens Act of 1698, which prohibited the export of woolen cloth beyond a colony's borders.
A. To protect English manufacturers of woolen goods both against American and Irish competition, England passed the Woolens Act of 1698
B. In order to protect English manufacturers of woolen goods against both American and Irish competition, England passed the Woolens Act of 1698
C. In order to protect English manufacturers of woolen goods against American, as well as against Irish, competition, the Woolens Act of 1698 was passed by England
D. For protecting English manufacturers of woolen goods against American, as well as Irish, competition, England passed the Woolens Act of 1698
E. For the protection of English manufacturers of woolen goods against both American and Irish competition, the Woolens Act of 1698, passed by England

The correct answer is B:
"...England passed the Woolens Act of 1698, which prohibited the export of woolen cloth beyond a colony's borders."

The closest grammatically eligible referent for which is "1698". However, here which points to the entire noun phrase "Woolens Act of 1698".