Sentence Correction

Scientists believe that unlike the males of most species of moth, the male whistling moths of Nambung, Australia, call female moths to them by the use of acoustical signals, but not olfactory ones, and they attract their mates during the day, rather than at night.
(A) by the use of acoustical signals, but not olfactory ones, and they attract
(B) by the use of acoustical signals instead of using olfactory ones, and attracting
(C) by using acoustical signals, not using olfactory ones, and by attracting
(D) using acoustical signals, rather than olfactory ones, and attract
(E) using acoustical signals, but not olfactory ones, and attracting

Answer is c or d? Please expalin.

i think the answer is 'd'..

The right Answer is D, "By using is redundant" (so C is out)
also, rather than is preferable than "not using"

One more point to add.

parallelism:
note that every option has "and". so think of || lism.

...., call female......... and attract .....
D only obeys this.

hence D
is the option that makes it parallel (||) construction

I would also go for option D

Someone please explain this question in detail.

Thanks.

mankey wrote:Someone please explain this question in detail.

Thanks.

after getting rid off the unnecessary words, we have -

...the male ... call female moths to them using acoustical signals, rather than olfactory ones, and attract their mates during the day, rather than at night.

please see that now the verbs "call" and "attract" are parallel.

hope it is clear now. if not, please let me know what exactly confuses you.

leo wrote:Scientists believe that unlike the males of most species of moth, the male whistling moths of Nambung, Australia, call female moths to them by the use of acoustical signals, but not olfactory ones, and they attract their mates during the day, rather than at night.
(A) by the use of acoustical signals, but not olfactory ones, and they attract
(B) by the use of acoustical signals instead of using olfactory ones, and attracting
(C) by using acoustical signals, not using olfactory ones, and by attracting
(D) using acoustical signals, rather than olfactory ones, and attract
(E) using acoustical signals, but not olfactory ones, and attracting

Answer is c or d? Please expalin.

In C, the entire phrase by using acoustical signals...and attracting their mates serves as an adverb describing HOW the male moths call female moths. HOW do the male moths call female moths? By attracting their mates. The implied meaning here is strange: that the male moths call females moths by attracting the MATES OF THE FEMALE MOTHS -- clearly not the intention of the sentence.

In D, the parallel verbs CALL and ATTRACT correctly convey the two actions that are being attributed to the male moths: they CALL female moths to them by using acoustical signals...and ATTRACT their mates during the day, rather than at night.

The correct answer is D.

Hello Mitch,
Can you please explain why E is wrong?

Thanks

happymanocha wrote:Hello Mitch,
Can you please explain why E is wrong?

Thanks

For the same reason that C is wrong: attracting their mates seems to function as an adverb indicating HOW the male moths CALL female moths. In my post above, I explain why this phrasing does not convey the intended meaning.

Hello Mitch,
Can you please explain why A is wrong?
In option A doesn't "they" clearly refer to the male whistling moths?

In option D should't "them" be themselves i.e subject and object of the sentence are the same then don't we need reflective pronoun?

Cheers

gmatguru,
is the following an error in C:
by using acoustical signals, not [by] using olfactory ones, and by attracting --> the [RED] portion is dropped,resulting into an incorrect parallelism grammatically.

GMATGuruNY wrote:By attracting their mates. The implied meaning here is strange: that the male moths call females moths by attracting the MATES OF THE FEMALE MOTHS -- clearly not the intention of the sentence.

not able to get how this interpretation works ?

we know that them,they,their should refer to same antecedent noun in GMAT, therefore as them here refers to the male moths, so their should also refer to the male moths. right ?

if so, then their mates should not imply "MATES OF THE FEMALE MOTHS", I guess!

can you please clarify ?

ngk4mba3236 wrote:gmatguru,
is the following an error in C:
by using acoustical signals, not [by] using olfactory ones, and by attracting --> the [RED] portion is dropped,resulting into an incorrect parallelism grammatically.

The issue is less about parallelism and more about function and meaning.
C: Male whistling moths call female moths by using acoustical signals, not using olfactory ones.
Here, the two colored portions are parallel.
But the function of the red phrase is unclear.
The red phrase could be a GERUND serving as the object of the preposition by.
The red phrase could be a COMMA + VERBing modifier serving to modify the preceding subject and verb.
Since the function of the red phrase is not crystal clear, the structure is not viable.

GMATGuruNY wrote:By attracting their mates. The implied meaning here is strange: that the male moths call females moths by attracting the MATES OF THE FEMALE MOTHS -- clearly not the intention of the sentence.

not able to get how this interpretation works ?

we know that them,they,their should refer to same antecedent noun in GMAT, therefore as them here refers to the male moths, so their should also refer to the male moths. right ?

if so, then their mates should not imply "MATES OF THE FEMALE MOTHS", I guess!

can you please clarify ?

Whether their serves to refer to male moths or to female moths, the resulting meaning is nonsensical.
For this reason, the intended referent for their is not crystal clear.
If their serves to refer to male whistling moths, we get:
Male whistling moths call female moths to them by attracting the male whistling moths' mates.
Conveyed meaning:
Male whistling moths use the process of attracting their MATES to call FEMALE MOTHS WHO ARE NOT THEIR MATES.
Not the intended meaning.
Eliminate C.

GMATGuruNY wrote:

leo wrote:Scientists believe that unlike the males of most species of moth, the male whistling moths of Nambung, Australia, call female moths to them by the use of acoustical signals, but not olfactory ones, and they attract their mates during the day, rather than at night.
(A) by the use of acoustical signals, but not olfactory ones, and they attract
(B) by the use of acoustical signals instead of using olfactory ones, and attracting
(C) by using acoustical signals, not using olfactory ones, and by attracting
(D) using acoustical signals, rather than olfactory ones, and attract
(E) using acoustical signals, but not olfactory ones, and attracting

Answer is c or d? Please expalin.

In C, the entire phrase by using acoustical signals...and attracting their mates serves as an adverb describing HOW the male moths call female moths. HOW do the male moths call female moths? By attracting their mates. The implied meaning here is strange: that the male moths call females moths by attracting the MATES OF THE FEMALE MOTHS -- clearly not the intention of the sentence.

In D, the parallel verbs CALL and ATTRACT correctly convey the two actions that are being attributed to the male moths: they CALL female moths to them by using acoustical signals...and ATTRACT their mates during the day, rather than at night.

The correct answer is D.

Hi GMATGuru,

I have question, should not choice D has 'comma' before 'using...'. My reasoning could be illustrated by following examples.

I killed the thief, using a gun. Meaning: I killed him by my gun.

I killed the thief using a gun. Meaning: i killed the thief WHO use a gun.

Similarly like in my 2 examples, I understood that 'call... them using .....' as same way. implied meaning for me: males call female to them (males) that use acoustical signals. I believe it wrong as we need to know HOW males attract females. I'm confused about 'using' in choice D.

In Verbal Review Q8, I provide another SC with OA

As the cost of wireless service has steadily dropped over the last year and as mobile phones have become increasingly common, many people are finding that they can avoid toll charges on their home phones by using their mobile phones to make long-distance calls at night or on weekends, whenmany wireless companies provide unlimited airtime for a small monthly fee.

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

Choice D is wrong because 'phone using mobile' is nonsensical meaning that implies that phones are human and use phones.


Another OG example while it was non underline part:

There are several ways to build solid walls using just mud or clay, but the most extensively used method has been the to form the mud or clay into bricks, and, after some preliminary air drying or sun drying, to lay them in the wall in mud mortar.

Here, the sentence say "walls using mud or clay' while it could gave the nonsensical meaning . I can interpret it is 'walls that use mud'the same 'phone using mobile'.

It seems there is inconsistency when dealing with 'using' and 'by using'
What is the difference among the whole cases?



Thanks in advance

Mo2men wrote:Hi GMATGuru,

I have question, should not choice D has 'comma' before 'using...'. My reasoning could be illustrated by following examples.

I killed the thief, using a gun. Meaning: I killed him by my gun.

I killed the thief using a gun. Meaning: i killed the thief WHO use a gun.

Similarly like in my 2 examples, I understood that 'call... them using .....' as same way. implied meaning for me: males call female to them (males) that use acoustical signals. I believe it wrong as we need to know HOW males attract females. I'm confused about 'using' in choice D.

In Verbal Review Q8, I provide another SC with OA

As the cost of wireless service has steadily dropped over the last year and as mobile phones have become increasingly common, many people are finding that they can avoid toll charges on their home phones by using their mobile phones to make long-distance calls at night or on weekends, whenmany wireless companies provide unlimited airtime for a small monthly fee.

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

Choice D is wrong because 'phone using mobile' is nonsensical meaning that implies that phones are human and use phones.


Another OG example while it was non underline part:

There are several ways to build solid walls using just mud or clay, but the most extensively used method has been the to form the mud or clay into bricks, and, after some preliminary air drying or sun drying, to lay them in the wall in mud mortar.

Here, the sentence say "walls using mud or clay' while it could gave the nonsensical meaning . I can interpret it is 'walls that use mud'the same 'phone using mobile'.

It seems there is inconsistency when dealing with 'using' and 'by using'
What is the difference among the whole cases?



Thanks in advance

The structure in the OA is as follows:
CLAUSE + NO COMMA + using.
In this structure, using may serve to refer to the preceding SUBJECT if the intended meaning is crystal clear.

Rule:
A VERBing modifier cannot serve to modify a third-person pronoun serving as the object of preposition (to him, for her, from them, by it, etc.) .

OA: Male whistling moths call female moths to them using acoustical signals.
Here -- in accordance with the rule above -- using cannot serve to modify to them.
For this reason, it is crystal clear that using serves to refer not to them but to male whistling moths (the preceding subject).
Conveyed meaning:
MALE WHISTLING MOTHS are USING acoustical signals.

SC11 in the OG12:
There are several ways to build solid walls using just mud or clay.
Here, the walls are to be BUILT and thus do not yet exist.
For this reason, no reader will construe that WALLS are using just mud or clay.
From context, it is crystal clear that using serves to refer not to walls but to the implied agent of to build.
Conveyed meaning:
Whoever intends TO BUILD solid walls will be USING just mud or clay.

SC8 in the OA for Verbal, answer choice D:
Many people are finding that they can avoid toll charges on their home phones using their mobile phones.
Here, a reader might construe that using serves to refer to home phones, conveying that HOME PHONES are USING mobile phones to achieve a particular result.
Since the intended meaning is NOT crystal clear, the structure here Is not viable.
Eliminate D.