As the cost of wireless service has steadily dropped over the last

a) phones, using their mobile phones for making long-distance calls at night or on weekends, at a time which Wrong - "which" cannot be a relative pronoun for time. Time must be "in which", "that", or "when".

b) phones, instead using mobile phones to make long-distance calls during the night of weekends, during which Wrong - "instead using" is an idiom not used correctly; "during which" is redundant and imprecise.

c) phones by using their mobile phones to make long-distance calls at night or on weekends, when Correct

d) phones using mobile phones for making long-distance calls during the night or weekends, when Wrong - "using" cannot modify phones

e) phones when using their mobile phones to make long-distance calls at night or on weekends, a time which. Wrong - "when" cannot describe phones; "which" cannot modify a time.

IMO C

I wouldn't make the blanket statement that "which" CANNOT be used to refer to time. It depends on the context. Here are a few examples with "which..." clauses that modify "time":

"Tim has some free time, which he feels guilty about wasting."
"Time, which was thought to be constant, is actually relative, according to some guy named Albert."
"The meeting will be postponed to a later time, which will be determined by the boss."

And here are some with "when..." clauses that modify "time":

"The meeting will be held at a time when all participants will be in town."
"I look forward to a time when pizza can be 3D-printed at home."
"I remember a time when pizza cost 10 cents a slice."

That said, you can kill both (A) and (B) for logic problems.


At first glance, it looks like the companies are providing time itself. This is nonsense, and it makes the subsequent phrase confusing, at best. A company can provide airtime, but not the abstract notion of moments passing. So while "which" can theoretically refer to time, in (A) it produces a problematic meaning. This is enough to get rid of (A).


I'm not sure what a "night of weekends" is, but it sounds pretty fun. Are we cramming multiple weekends into a Thursday night? College students certainly try, but on the GMAT, this phrase is illogical.

I hope that helps!

When we see an "-ing" modifier following a full clause and a comma, we can assume that the "-ing" is describing the previous clause, giving us either a consequence of the previous action or context for that action.

Take another look at the relevant portion of (A):


Here "using" appears to give us context for the previous action, informing us how people are avoiding toll charges. Makes sense to me. So I wouldn't eliminate (A) for this usage. (But, as others have noted, there's a problem with the phrase "at a time which," and this is the reason to get rid of the option.)

I hope that clears things up!

No, I don't like the comma+ing in (A).
comma + ing is used to provide cause-effect relation or additional information about the previous subject/clause.
The sentence here intends to tell you that people are avoiding toll charges on home phones by using their mobile phones at opportune times. With a comma + ing that meaning is lost.

When adverbial phrases are used after the verb, we normally do not use a comma.

... many people are finding that they can avoid toll charges on their home phones by using their mobile phones for making long-distance calls at night or on weekends ...

The reason most people have ignored it is that "which/when" decision point is obvious. For a point in time, we use "when", not "which".

You don't need a comma before "using" in your example. We usually do not put a comma in such situations.
As for what constitutes a deterministic error, that depends on what options you have. Language and "rules" are flexible depending on what you want to convey and the best possible way available to convey it. That is why I often use words such as "usually", "often" etc when spelling out what is acceptable usage and what is not.
You have an added constraint of limited options in GMAT questions. Use them to your advantage. If a list of rules were all that were needed to ace SC, this type of questions would not have been tested on GMAT.

Hi Karishma,

Joe called his parent, using his new phone.

I think the above sentence is perfectly fine because the verb ing presents the additional information: How did Joe call? He called using his new phone.

And I think same is the case with the question's A part.


Main Qn: many people are finding that they can avoid toll charges on their home phones, using their mobile phones for making long-distance calls at night or on weekends

How can they avoid toll? By using....

My question is would you reject an option SOLELY on this usage of verb-ing? I am just comparing it with the example I gave and it seems like verb-ing here is not a deterministic error. Can you please help me?

Thank you in advance!

VeritasKarishma GMATNinja

In Option C, if we change this highlighted portion
phones by using their mobile phones to make long-distance calls at night or on weekends, when

and convert this option into the following sentence(this change taken from option D)
phones by using their mobile phones to make long-distance calls during the night or weekends, when

Will both the versions be correct?

Hello gaitbhu,

I will be glad to help you with this one.

IMHO, the modified version of the sentence would also present the same meaning.

However, I wonder what could be the significance of this modification.


Hope this helps.
Thanks.
Shraddha

When you see the phrase ‘at a time which’ you should realise that this is incorrect.
‘When’ is the correct preposition of time that’s to be used here.

(A) phones, using their mobile phones for making long-distance calls at night or on weekends, at a time which

(B) phones, instead using mobile phones to make long-distance calls during the night of weekends, during which

(C) phones by using their mobile phones to make long-distance calls at night or on weekends, when

(D) phones using mobile phones for making long-distance calls during the night or weekends, when

(E) phones when using their mobile phones to make long-distance calls at night or on weekends, a time which

For this reason, we can eliminate Options A, B and E.

Option D is incorrect for ‘phones using mobile phones’ which is not the intended meaning.
Plus, there is also the unidiomatic ‘for’ used in this option. Eliminate.

Option C is the best option.

Hope this helps!

GMATNinja Just want to be crystal clear, but can "which" NOT be used to refer to time? Also, if time permits, would you please provide some feedback on my analysis?

(A) phones, using their mobile phones for making long-distance calls at night or on weekends, at a time which
(1) “which” can’t be used for time; (2) “for making” is unidiomatic – should be “to make”

(B) phones, instead using mobile phones to make long-distance calls during the night of weekends, during which
(1) “which” can’t be used for time; (2) is there anything wrong with "instead" here? Experts please help

(C) phones by using their mobile phones to make long-distance calls at night or on weekends, when
(1) “which” can’t be used for time;

(D) phones using mobile phones for making long-distance calls during the night or weekends, when
(1) “…on their home phones using mobiles phones…” – this is illogical and therefore, incorrect; (2) “for making” is unidiomatic – should be “to make”

(E) phones when using their mobile phones to make long-distance calls at night or on weekends, a time which
(1) “when” needs to modify a time, not “phones”; (2) “which” can’t be used for time;

Hi VeritasKarishma GMATNinja EducationAisle, given none of the post mentioned about the usage of 'ing' participle in option A here, I wanted to check if the 'ing' modifier is used here correctly and if yes what does it modifies?

Thanks a lot GMATNinja for the clarification, can you confirm if option B would have dropped "by" and put a comma instead, phones, using their mobile phones to make long-distance calls at night or on weekends, when it would have still be correct?

Dear RohitSaluja
I presume that you have modified option "C"; in this case, I would say that such construction would be arguably correct, with proviso.
Yes, adverbial modifier modifies entire clause and thus provides descriptive info how the result of savings can be achieved. Yet, because modifier set off by commas, we can drop it and thus lose the intended meaning.

....many people are finding that they can avoid toll charges on their home phones, using their mobile phones to make long-distance calls at night or on weekends, when many wireless companies provide unlimited airtime for a small monthly fee.

Does the aforementioned version make sense ?)

Hello RohitSaluja,

We hope this finds you well.

To answer your query, yes; assuming you meant to say C rather than B, replacing "by" with a comma would produce a grammatically correct construction, though it would be slightly less clear than the original.

We hope this helps.
All the best!
Experts' Global Team

(A) phones, using their mobile phones for making long-distance calls at night or on weekends, at a time which

KarishmaB
Please help me to understand how to reject basis illogical meaning. How "at a time which" provides illogical meaning?

Thanks

Consider a simple example:

A can avoid B by doing C.
A can avoid B, doing C.

Which is better? The first sentence is clear in its meaning and it is the meaning we want to convey. The second sentence is not. The main clause seems incomplete and the relation of the modifier with the main clause is not clear.
Option (A) has the structure of the second sentence and hence it is not the best option.

To specify time, we use 'when.' When we want to talk about a particular point in time, we use 'when' as the relative pronoun. It can be replaced with 'then' in the modifying clause.

The time when you visited me was precious.
The time was precious. You visited me then.

We can replace 'when' with 'on which,' 'at which' or 'in which' as the case may be (though 'when' is direct and concise)
Examples:
The day on which you visited me was precious. (You visited me on that day)
The year in which you visited me was precious. (You visited me in that year)
The moment at which I saw you was memorable. (I saw you at that moment)


When we talk about the noun 'time,' we can use 'which'.

I will visit you some time in the future, a time which will be decided by my circumstances.

We need to replace 'which' with the noun 'time'. The time will be decided by my circumstances. We cannot replace it with 'then' here.


Hence, in our original sentence, the following two sentences will work:

... at night or on weekends, when many companies provide unlimited airtime.
many companies provide unlimited airtime then.

... at night or on weekends, a time at which many companies provide unlimited airtime. (less preferable)
many companies provide unlimited airtime at that time.


But this sentence will not work:
... at night or on weekends, at a time which many companies provide unlimited airtime.
Here, 'which' is replacing 'a time' not 'at a time.'

So it becomes 'many companies provide unlimited airtime a time' - Incorrect.

The preposition 'at' is a part of the previous clause. So something like this could work:
People can call at night, on weekends, or at a time at which many companies provide unlimited airtime.
though preferable would be
People can call at night, on weekends, or at a time when many companies provide unlimited airtime.

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