Since 1990 the global economy has grown more than it did

[JustinCKN]

Ron:
I will obey the forum rule strictly.
Sorry.

[RonPurewal]

excellent.

[LOW486]

I read through all the thread, but I am still confused with Choice B.

so Ron could you explain Choice B in another way

THANKS IN ADVANCE!

[RonPurewal]

hi, that's not a fair question.
if you're still confused after reading through a thread with almost a hundred posts, then, you must have some SPECIFIC issue(s) with that choice.

...so, please ask at least one SPECIFIC question about that answer choice.
thanks.

[MollyL456]

hi Ron
I am confused about the beginning of agriculture in A. I think that the meaning of words follow from should parallel with the meaning of words follow to，so maybe the words after from should mean a certain time like 1950？

Besides，I don't think that the beginning of agriculture can mean a certain time，because of the following example in OG.

10. The widely accepted big bang theory holds that the universe began in an explosive instant ten to twenty billion years ago and has been expanding ever since.

　　(A) that the universe began in an explosive instant ten to twenty billion years ago and has been expanding

　　(B) that the universe had begun in an explosive instant ten to twenty billion years ago and had been expanding

　　(C) that the beginning of the universe was an explosive instant ten to twenty billion years ago that has expanded

　　(D) the beginning of the universe to have been an explosive instant ten to twenty billion years ago that is expanding

　　(E) the universe to have begun in an explosive instant ten to twenty billion years ago and has been expanding

C is wrong，because the beginning of universe was not a instant.

So please explain the problem why the beginning of agriculture isn't parallel with1950.
Thank you!!!

[Sage Pearce-Higgins]

The parallelism between 'the beginning of agriculture' and '1990' is fine. After all, they are both points in time. (I mean, who knows exactly in what year agriculture began!). You've taken the parallelism rule and applied it in too extreme a way: the form of words doesn't have to be exactly the same. Be sure that the new knowledge of SC that you're gathering doesn't completely undermine your existing knowledge of English.

We can't discuss OG problems here - check out the Navigator explanation.

[JustinCKN]

Dear Ron and Manhattan Staffs,
from

ayushrastogi82 wrote:I've learned one rule on the basis of which I marked off A, but now I'm very confused.

Rule: when "have/has/had" is an aulixiary verb, you do have a choice to repeat or not repeat the past participle, but you cannot change "have/has/had" to "do/does/did"

For example:
John has always eaten more meat than Paul has eaten.(correct)
John has always eaten more meat than Paul has. (correct)
John has always eaten more meat than Paul does. (incorrect)

A says: Since 1990 the global economy has grown more than it did during the 10,000 years from the beginning of agriculture to 1950

If OA is A, then it is voilating this rule.

The only difference I can point out between the rule and the choice A is that the above mentioned rule has 2 different subjects while choice A has only one subject.

Could any instructor clarify on the same?


read here:
http://www.beatthegmat.com/soar-t62473-15.html#280069

note that this sentence fits the third form given in that post -- "did" is a form of "to do", and "has grown" is a tense of the action verb "grow" (it's called the "present perfect tense", if you like to name these things)

notice that the reverse of this kind of structure would not be permissible; if you had just "has" as the second part of the parallel structure, then that's no longer the present perfect tense of an action verb, and so in that case you would also need a corresponding form of "have" in the first part.

I have read through the detailed analysis, but I still don't understand this part

notice that the reverse of this kind of structure would not be permissible; if you had just "has" as the second part of the parallel structure, then that's no longer the present perfect tense of an action verb, and so, in that case, you would also need a corresponding form of "have" in the first part.

Can you do me a favor by giving me an example to explain that?

have a good one!
Regards,
Justin

[TiffanyB]

Hello Justin,

It appears that ayushrastogi82 is continuing to discuss the parallel structures that they mentioned earlier in the post.

They provided these examples, which are correct. They each compare the quantity of meat eaten by Justin to the quantity of meat eaten by Paul. In the third example, does is incorrectly used to reference has eaten. The "has" structure needs another "has" in this case to retain a correctly parallel structure in the comparison.

For example:
John has always eaten more meat than Paul has eaten.(correct)
John has always eaten more meat than Paul has. (correct)
John has always eaten more meat than Paul does. (incorrect)

It seems that in the next section, they hypothesize about the opposite of this structure.

Notice that the reverse of this kind of structure would not be permissible; if you had just "has" as the second part of the parallel structure, then that's no longer the present perfect tense of an action verb, and so in that case you would also need a corresponding form of "have" in the first part.

I take this to mean an example like this:
John has always run more than Paul has run. (correct)
John has always run more than Paul has. (correct)
John runs more than Paul has run. (incorrect)

In reading the post information that you provided, this is how I would interpret the final 2 paragraphs that ayushrastogi82 posted.

[JustinCKN]

I take this to mean an example like this:
1.John has always run more than Paul has run. (correct)
2.John has always run more than Paul has. (correct)
3. John runs more than Paul has run. (incorrect)

Hi TiffanyB,

thank you for your detailed explanation.
I have two questions:

1. I have read another post from Ron to get this example:
It's a helping verb. It implies "have ___ed", parallel to some verb on the other side.

I am now making more money than I ever have before.

this example departure from #.3 John runs more than Paul has run. (incorrect)

I understand that we have to obey the rule admitted by GMAT, so i wanna ask which rule is admitted at this time by GMAC?

2. John has always eaten more meat than Paul does. (incorrect)

I think it should e correct.

i get the rule from another website
'if you use did/do/does to stand for an action verb, then it can be parallel to any tense of that action verb.
just like this question:
Since 1990 the global economy has grown more than it did during the 10,000 years from the beginning of agriculture to 1950.

A) Since 1990 the global economy has grown more than it did during the 10,000 years from the beginning of agriculture to 1950.
OA=A,
in the second part of the comparison 'did' stands for 'has grown ' in the 1st part of the comparison.

THX
Have a good one!

Justin

[TiffanyB]

The examples that you note below each offer something that my examples do not: context.

It's a helping verb. It implies "have ___ed", parallel to some verb on the other side.

I am now making more money than I ever have before.

this example departure from #.3 John runs more than Paul has run. (incorrect)

Your example offers the time periods being compared. I am now making more money than I ever have before.
In my example, John runs now, but more than Paul has run...this week? in his entire life? The meaning is unclear without a time marker.

I take this to mean an example like this:

2. John has always eaten more meat than Paul does. (incorrect)

I think it should e correct.

i get the rule from another website
'if you use did/do/does to stand for an action verb, then it can be parallel to any tense of that action verb.
just like this question:
Since 1990 the global economy has grown more than it did during the 10,000 years from the beginning of agriculture to 1950.

A similar issue appears here.

Your example from the problem in this thread offers a comparison between two time periods: 1990 to now and the 10,000 years that start with the beginning of agriculture and end with 1950.

In my example, John has always eaten more meat (his entire life?) than Paul does (now?). A better structure would be "John has always eaten more meat than Paul has" or "John eats more meat than Paul does."

Thanks Justin!

[JustinCKN]

Hi TiffanyB,
Thanks for your detailed explanation. I think I should spend more time thinking about meaning to solve problems.

Have a good one!

[TiffanyB]

My pleasure, JustinCKN!

Thinking about your process to solve problems can often be helpful.