By sucking sap from the young twigs of the hemlock tree,

Question

By sucking sap from the young twigs of the hemlock tree,  tree growth is retarded by the woolly adelgid, causing needles to change color from deep green to grayish green and to drop  prematurely.

A. tree growth is retarded by the woolly adelgid, causing needles to change color from deep green to grayish green and to drop
B. tree growth is retarded by the woolly adelgid, and this causes the color of needles to change from deep green to grayish green, and their dropping
C. the woolly adelgid retards tree growth, which causes needles to change color from deep green to grayish green, and dropping
D. the woolly adelgid retards tree growth, causing needles to change color from deep green to grayish green and to drop 
E. the woolly adelgid retards tree growth, and this causes the color of needles to change from deep green to grayish green, and the their dropping

anairamitch1804 · Accepted Answer

The sentence begins with a modifier. So, when we get to the comma, we should stop and ask the question that the modifier raises. Here the question is,  "Who or what sucks sap from young twigs?"  The part immediately following the comma should answer our question in a logical manner.

A. tree growth is retarded by the woolly adelgid, causing needles to change color from deep green to grayish green and to drop 
Tree growth sucks sap from young twigs? 
Makes no sense. Eliminate A.

B. tree growth is retarded by the woolly adelgid, and this causes the color of needles to change from deep green to grayish green, and their dropping 
Tree growth sucks sap from young twigs? 
Makes no sense. Eliminate B.

C. the woolly adelgid retards tree growth, which causes needles to change color from deep green to grayish green, and dropping 
The woolly adelgid sucks sap from young twigs? Makes sense - keep C for now.

D. the woolly adelgid retards tree growth, causing needles to change color from deep green to grayish green and to drop 
The woolly adelgid sucks sap from young twigs? Makes sense - keep D for now.

E. the woolly adelgid retards tree growth, and this causes the color of needles to change from deep green to grayish green, and the their dropping 
The woolly adelgid sucks sap from young twigs? Makes sense - keep E for now.

Now, compare C, D and E for other issues.

Note: The retarded tree growth causes 2 things: 
1) needles change color 
2) needles drop prematurely.

We need parallelism here.

C. the woolly adelgid retards tree growth, which causes needles to change color from deep green to grayish green, and dropping 
Not parallel. Eliminate.

D. the woolly adelgid retards tree growth, causing needles to change color from deep green to grayish green and to drop 
Parallel. Keep.

E. the woolly adelgid retards tree growth, and this causes the color of needles to change from deep green to grayish green, and the their dropping 
Not parallel. Eliminate.

Answer is D.

thangvietname · Answer

pls, help

the word "this" in E is right or wrong. Pls, explain.

tuanquang269 · Answer

"this" in choice E is totally wrong, this does not refer to anything. If you use "this action (of the woolly adelgid), it will be ok.

Furthermore, choice E make parallelism in the modifier-part with 2 ambiguous items "this" vs "the their dropping".

santoshsurathkal · Answer

By sucking sap from the young twigs of the hemlock tree, <<tree growth is retarded by the woolly adelgid, causing needles to change color from deep green to grayish green and to drop>> prematurely.

A. tree growth is retarded by the woolly adelgid, causing needles to change color from deep green to grayish green and to drop
B. tree growth is retarded by the woolly adelgid, and this causes the color of needles to change from deep green to grayish green, and their dropping wrong ....

C. the woolly adelgid retards tree growth, which causes needles to change color from deep green to grayish green, and dropping (and dropping is not parallel to any part of the sentence)
D. the woolly adelgid retards tree growth, causing needles to change color from deep green to grayish green and to drop
E. the woolly adelgid retards tree growth, and this causes the color of needles to change from deep green to grayish green, and the their dropping
(( their refers to what? ))

daagh · Answer

A and in fact B are most certainly grammatically wrong becos they belong to the classic case of misplaced modification.The participial modifier   By sucking sap from the young twigs of the hemlock tree  should be followed by the modified noun namely t he woolly adelgid  rather than  the tree growth . A and B mean as if the tree growth is sucking sap.

knuckleduster · Answer

Can we eliminate E on the grounds that 'their dropping' is awkward

sayantanc2k · Answer

In general a possessive noun / pronoun + gerund is perfectly valid combination. The following link will probably be helpful to get a better concept on this topic: https://www.english-for-students.com/Pos ... runds.html

Skywalker18 · Answer

By sucking sap from the young twigs of the hemlock tree,  tree growth is retarded by the woolly adelgid, causing needles to change color from deep green to grayish green and to drop  prematurely.

A. tree growth is retarded by the woolly adelgid, causing needles to change color from deep green to grayish green and to drop - Modifier issue -- tree growth is not sucking sap
B. tree growth is retarded by the woolly adelgid, and this causes the color of needles to change from deep green to grayish green, and their dropping - same as A
C. the woolly adelgid retards tree growth, which causes needles to change color from deep green to grayish green, and dropping - incorrect usage of which to refer to growth
D. the woolly adelgid retards tree growth, causing needles to change color from deep green to grayish green and to drop - Correct
E. the woolly adelgid retards tree growth, and this causes the color of needles to change from deep green to grayish green, and the their dropping - Parallelism issue and usage of and changes meaning

Answer D

jibberjabber · Answer

Can someone please explain why is the answer choice D and not C.

AjiteshArun · Answer

The  which  in option C is ambiguous (it could refer to  tree growth ).  Dropping  is not correct either (in option D  to change  and  to drop  are parallel).

... the woolly adelgid retards tree growth,  which  causes needles to change color from deep green to grayish green, and  dropping ...

CrackverbalGMAT · Answer

The question tests the concept of Modifiers.

The sentence begins with the modifier “By sucking sap from the young twigs of the hemlock tree”. The word after the comma becomes the subject of the modifier. In Options A and B, the noun phrase after the comma is “the tree growth”, implying that the tree growth is the one that sucks sap from the young twigs of the hemlock tree.  So, Options A and B can be eliminated.

Options C, D, and E have the noun phrase “the woolly adelgid” immediately after the comma. This noun phrase is a suitable subject for the modifier. 
There is a second modifier “which causes needles to change color from deep green to grayish green” in the sentence. The second modifier in the sentence describes the result of the clause “the woolly adelgid retards tree growth” and so, is supposed to modify the entire clause. But a relative pronoun directly refers to the noun before it, which is “tree growth” in Option C.  So, Option C can be eliminated.

In Option E, the form of the second modifier has been changed to that of an independent clause “and this causes the color of needles to change from deep green to grayish green” joined to the rest of the sentence with the conjunction ‘and’. This option has an ambiguous pronoun ‘this’. A pronoun refers to a noun or a noun phrase but not to an entire clause, thereby making the pronoun ‘this’ an ambiguous one without a proper antecedent.  So, Option E can also be eliminated.

Option D has the appropriate structure. It correctly puts the phrase “the woolly adelgid” after the first modifier. D also has a participle modifier to modify the clause, conveying the meaning accurately.
 Therefore, Option D is the most appropriate.

Jayanthi Kumar.

AmarpreetK · Answer

Look at the opening of the sentence  'By sucking sap from the young twigs of the hemlock tree '; this is a modifier which tells us that 'Someone of something is sucked/is sucking the sap from young twigs of hemlock tree' - ask the question  'Who/What is sucking the sap?'.

Then move forward to the next part of the sentence  'tree growth is retarded by the woolly adelgid' '; here we will find the answer to above question - 'Is it tree growth sucking the sap'? Makes no sense. Therefore, reading the sentence till now we know that the woody adelgid sucks the sap from young twigs.

Based on this, eliminate A and B because the modified entity (which is a noun) is wrongly placed too far. Keep C, D and E.  Now move forward evaluating these three choices and spotting the errors.
Note the difference in the three choices:
 C: 'which causes' ; 'and dropping'
D: 'causing' ; 'and to drop'
E: 'and this causes' ; 'and the their dropping

'And' is a parallelism marker. In parallelism, once you have spotted a parallelism marker, the next step is to look for parallel elements in order to verify if the marker justifies its presence in the sentence.  As per the meaning of the sentence, 'The retarding of tree growth is causing the needles to do two things - change color and drop prematurely'. Now, the next step is to look for these parallel elements in the answer choice where the meaning is also clear.

C: which causes needles  to change color  from deep green to grayish green,  and   dropping  
'to change color' and 'dropping' is not parallel

D: causing needles  to change colo r from deep green to grayish green  and   to drop  
'to change' and 'to drop' is parallel.

E: and  this causes the color  of needles to change from deep green to grayish green,  and   the their dropping 
Not parallel

Therefore  the answer choice D is correct  because it shows parallelism with correct placement of markers and without distorting the meaning of the sentence

VerbalBot · Answer

Automated notice from GMAT Club VerbalBot: 

A member just gave Kudos to this thread, showing it’s still useful. I’ve bumped it to the top so more people can benefit. Feel free to add your own questions or solutions.

 This post was generated automatically.

By sucking sap from the young twigs of the hemlock tree,

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

GMAT Sentence Correction (SC - EA only) Questions

By sucking sap from the young twigs of the hemlock tree,

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia