I want to know what are Subgroup modifiers, how they

Question

I want to know what are Subgroup modifiers,  how they function,how they are created & how they are tested on GMAT.

As per Manhattan GMAT
Subgroup Modifiers- When you want to describe a part of a larger group with a modifier, use one of the following three Subgroup Modifier constructions.
Right: This model explains all known subatomic particles, SOME OF WHICH WERE only recently discovered.
Wrong: This model explains all known subatomic particles, SOME OF WHICH only recently discovered. -  Why this sentence is incorrect or why verb is required after WHICH 
Right: This model explains all known subatomic particles, SOME OF THEM only recently discovered. -  Why this sentence is correct even though verb is not present after them. 
Right: This model explains all known subatomic particles, SOME only recently discovered. -  Why this sentence is correct. 
Wrong: This model explains all known subatomic particles, OF WHICH SOME WERE only recently discovered.-  Why this sentence is incorrect.

Hope you don't mind taking time to explain these concepts.

With Regards,
Fame

mikemcgarry · Accepted Answer

Dear Fame , One of the strengths of MGMAT is that they are hyper-thorough about everything. In a way, a weakness of this approach is that they can get you to worry about something that's not particular common. I would estimate that if you took 20 GMATs in a row, you would only see "sub-group modifiers" once or twice. It's just not that common. First of all, what is a subgroup modifier? Suppose the main clause of a sentence is talking about some large group ---- the Japanese, the auto industry workers, sea mammals, small towns in the US Midwest, the integers, the elements on the Periodic Table, verbs in the French language, Oscar-winning movies, etc. etc. ---- any large group of anything. Suppose the main clause says something about this large group in its entirety, and we want to make a further clarification either about the whole group or about some part of the group ---- 1) All German people are blah blah blah, but some of them are blah blah blah . 2) Blah blah blah migratory birds, most of which are blah blah blah . 3) Blah blah blah subway trains in NYC, all having blah blah blah . Those underlined phrase are examples of grammatically correct sub-group modifiers --- modifiers which talk about either part of the whole group (as in #1 & #2) or which add further clarification to the whole group (#3). Keep in mind, first of all, that in any of these, the "part" word could be any of what MGMAT calls the SAMAN words ( some, any, none, all, more, most ) or any quantity word ( many, few, each, both, either, neither, half, one , etc.). Now, what's going on with the different grammatical structures following these? The words "which" and "who" & "whom" are relative pronouns --- these have to introduce a full + clause --- in fact, the relative pronoun will act as the noun in the clause, so it must be followed by a bonafide verb. 4) I admire firemen, few of whom would do X . = correct ("whom" is followed by a bonafide verb) 5) I have a low opinion of NY Yankees fans, many of whom doing X . = incorrect ("whom" + participle is not complete) 6) I read a book about Chinese dynasty, most of which lasted blah blah blah . = correct. same as #4 7) The city council took an extensive survey of houses in Berkeley, none of which having blah blah blah . = incorrect, same as #5 By contrast, suppose instead of a relative pronoun, we want to use an ordinary pronoun, "them" --- "some of them", "all of them", "most of them", etc. ---- now, this phrase is a noun, and we have two options (a) an absolute phrase = (b) a coordinating conjunction (e.g. "and", "or", "but", etc.) and another independent clause = + 8) She wrote her dissertation on mollusks, some of them growing blah blah blah. = correct, absolute phrase 9) The Protestant Churches believe blah blah blah, but some of them also believe blah blah blah. = correct, two independent clauses, correctly joined by a coordinating conjunction. 10) The winner carried Ohio in all president elections since 1964, two of them involved a major third-party candidate . = incorrect, run-on sentence = tow independent clauses not properly joined by a conjunction. The foregoing should explain why the correct sentence in the MGMAT are correct. Now, let's look at the sentences MGMAT cites as incorrect: 11) The Standard Model explains all known subatomic particles, of which some of them were only recently discovered . = Two pronouns = redundant. Basically you have a structure, as in " My friend he is intelligent ." This occurs in colloquial speech, but it is incorrect in formal speech and never will be acceptable on the GMAT. 12) The Standard Model explains all known subatomic particles, some of them which were were only recently discovered . This has the incorrect structure , as in " The store is open, the street which was recently paved. " = nonsense. That's the problem with this one. 13) The Standard Model explains all known subatomic particles, some of which only recently discovered . = same mistake as #5 & #7 above. Notice the general format can be correct if the noun is an appositive phrase modifying something in the sentence, such as 14) Lincoln was a noble man, a president who guided the country through wa r. = the noun "president" is an appositive, modifying either "man" or "Lincoln." The problem, though, is that a subgroup ("some of them", "most of them", etc.) can never be an appositive for the whole group, which is why this otherwise acceptable structure is illegal in this context. BTW, the "model" discussed in the MGMAT example sentences is known in Particle Physics as "the Standard Model", which is why I included this in the sentences. Does all this answer your questions? Mike :-)

shriramvelamuri · Answer

Hi Mike

Can I ask you one more question with subgroup modifier, please.

In the MGMAT there is this example in page no 240.

Right: This model explains all known subatomic particles, some of which were only recently discovered.

the associated example includes.,

Wrong: This model explains all known subatomic particles, some of which only recently discovered.

I understood that WERE is a must when using the which construction.

In the page no 250 MGMAT has a similar sentence that is correct according to MGMAT but the sentence is lacking WERE.

The houses on the canal street, many of which had been damaged in the storm, looked abandoned.

My question,

Is it compulsory to use the word WERE when referring to subgroup while the using the WHICH construction.

Please could you help me with this.

mikemcgarry · Answer

Dear shriramvelamuri , I'm happy to help. My friend, regardless of whether it is used in a subgroup modifier, the word " which ," ALWAYS introduces a subordinate clause, and in fact, it's always the subject of that subordinate clause. Thus, the word " which " must always be followed by a full verb. That's a rule you definitely need to know. Some full verbs involve " were " and some don't. I don't know where you found this "rule" that " which " must be followed by " were " when used in a subgroup modifier --- that is hogwash! The issue of subgroup modifiers is irrelevant to the questions about the use of " which ." The word " which " must always be followed by a full verb. The following are examples of full verbs, with X & Y a subjects: X sings. X and Y sing. X sang. X has sung. X and Y have sung. X will sing. X had sung. X is singing. X and Y are singing. X was singing. X & Y were singing. All of those are full verbs, of different tenses. A few tenses involve " were ," especially in a passive construction. My friend, I think you need to forget about subgroup modifiers for the moment and learn more about verbs and the various forms of verbs (tenses, subjunctive, active vs. passive) https://magoosh.com/gmat/2012/gmat-verb- ... ct-tenses/ https://magoosh.com/gmat/2012/gmat-verbs ... ive-tense/ https://magoosh.com/gmat/2012/active-vs- ... -the-gmat/ https://magoosh.com/gmat/2012/gmat-gramm ... ive-tense/ Subgroup modifiers is a rare topic that could appear on a single SC question on the GMAT. By contrast, verbs will be part of every single sentence, and many of the SC sentences on the GMAT will involve splits that change the form of verbs. Does all this make sense? Mike :-)

sourpatch · Answer

Hi Mike, thank you so much for your explanation. I had one follow-up question related to your response.

I now understand that there are a few options to deal with these types of modifiers. I've listed a few below:

Jane, John, and Joe were fired, all of them being terrible workers.
  Jane, John, and Joe were fired, all of whom were terrible workers.
  Jane, John, and Joe were fired, because all of them were terrible workers.

But, would the following sentence be correct? My goal was to use an appositive construction with one of MGMAT's SANAM pronouns.

Jane, John, and Joe were fired, all of the terrible workers.

Thanks!

mikemcgarry · Answer

Dear sourpatch , I'm happy to respond. :-)

My friend, I am going to caution you against creating your own example sentences, as none of these sentence are particularly GMAT-like. It's much better if you can find example sentence in context in sophisticated reading. A few comments. 1) For the Absolute Phrase Jane, John, and Joe were fired, all of them being terrible workers . The word " being " sounds awkward. A more sophisticated way to say this would be Jane, John, and Joe were fired, all of them terrible workers. In fact, instead of the comma after " fired ", I could imagine a writing using an em-dash. This gets into very sophisticated punctuation issues, well beyond the GMAT. 2) For the Appositive Phrase Your sentence sounds awkward. Also, notice that in this fourth sentence you changed the meaning from the first three. In the first three, these three workers were all terrible, but it left open the question whether there were also other terrible workers. In the fourth, it's clear that those three are the only three terrible workers, a very different meaning. With the first meaning, I would say: Jane, John, and Joe---all terrible workers---were fired. Setting off the appositive with em-dashes feels more natural. For the second meaning, I would say: All of the terrible workers---Jane, John, and Joe---were fired . Your examples with the Relative Pronoun and with the Subordinate Conjunction are fine. Does all this make sense? Mike :-)

sourpatch · Answer

Thanks, Mike. That makes sense! I appreciate your response.

TheRzS · Answer

Mr. McGarry - hats off to you sir.

shabuzen102 · Answer

Dear Mike,

Thank you for that very detailed explanation. Your explanation accounted for the first two examples “some of which were recently discovered” and “some of them discovered”

What about the third sentence? Which grammatical structure did it use when it said “some only recently discovered”? Or is it just the shortened version of “some of them only recently discovered”?

Thanks!

shabuzen102 · Answer

Dear Expert,

I originally directed this question at Mike McGarry. However, it looks like he hasn't been to GMATclub in a while, so I'd really appreciate any help/ explanation from other experts.

I compared among the three original sentences and I understand the first two sentences thanks to the very detailed explanation by Mike McGarry.

However, I did not understand the grammatical structure of the third sentence. Which grammatical structure did it use when it said ???some only recently discovered???? Or is it just the shortened version of ???some of them only recently discovered????

Moreover, these three examples were concerned with the passive voice (something WAS discovered by someone). However, how do we use these structures with active voice?

For example, what about a set of sentences like this - are these correct?

1. Kulaka trees usually have flowers, some of which have blue centers.
2. Kulaka trees usually have flowers, some of them having blue centers.
3. Kulaka trees usually have flowers, some having blue centers.

Thanks!

VerbalBot · Answer

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