A team of researchers reported that five endangered birds species had

A team of researchers reported that five endangered birds species had resumed nesting or investigated nesting boxes erected by volunteers having been ferried out to the island last month.

Now lets understand the message(meaning) the sentence is trying to convey.

Meaning:
A team of researchers reported that some birds have resumed nesting OR something that appears to be nesting but is not .

Another things to notice here is the parallelism between the verbs(gerunds) separated by OR.The first gerund is nesting so the second verb should be parallel to this . This leaves us with B,C and D.



(b) begun investigating nesting boxes erected by volunteers, being being implies that researchers are still being ferried and this makes no sense

(c) investigating nesting boxes, erected by volunteers, had <fluff> nesting OR investigating nesting boxes -- missing verb and not parrallel in structure.

(d) were investigating nesting boxes erected by volunteers structure (had and were are parallel) is good, gerunds are parrallel & meaning is crisp

Dear Friends,

Here is a detailed explanation to this question-
Meaning is crucial to solving this problem:
Understanding the intended meaning is key to solving this question; the meaning of the crucial part of this sentence is that five endangered bird species had resumed nesting or were investigating nesting boxes erected by volunteers who had been ferried out to the island last month.

Concepts tested here: Meaning + Modifiers + Parallelism + Verb Forms

• The simple past tense is used to refer to actions that concluded in the past.
• The introduction of the present participle ("verb+ing"- “being” in this case) after the comma generally leads to a cause-effect relationship.
• Any elements linked by a conjunction ("or" in this case) must be parallel.
• The pronoun “which” cannot be used to refer to a human being.

A: The sentence formed by this answer choice incorrectly uses the present participle ("verb+ing" - "having" in this sentence) phrase "having been ferried" to refer to an action that concluded in the past; remember, the simple past tense is used to refer to actions that concluded in the past.

B: The sentence formed by this answer choice alters the meaning of the sentence through the phrase "being ferried out"; the use of the "comma + present participle ("verb + ing" - "being" in this case)" construction incorrectly implies that five endangered bird species were investigating nesting boxes erected by volunteers because the bird species had been ferried out to the island last month; the intended meaning is that five endangered bird species were investigating nesting boxes erected by volunteers, and as a separate action the volunteers had been ferried out to the island last month; remember, the introduction of present participle ("verb+ing"- “being” in this case) after comma generally leads to a cause-effect relationship.

C: This answer choice fails to maintain parallelism between the active verb "had resumed nesting" and the present participle "investigating"; remember, any elements linked by a conjunction ("or" in this case) must be parallel.

D: Correct. The sentence formed by this answer choice uses the phrase "ferried out to the island last month", conveying the intended meaning - that five endangered bird species were investigating nesting boxes erected by volunteers, and as a separate action the volunteers had been ferried out to the island last month. Further, Option D avoids the pronoun error seen in Option E, as it uses no pronouns. Additionally, Option D correctly uses the past participle "ferried" to refer to an action that concluded in the past. Besides, Option D maintains parallelism between the active verb phrases "had resumed nesting" and "were investigating".

E: The sentence formed by this answer choice incorrectly refers to "volunteers" with the pronoun "which"; remember; the pronoun “which” cannot be used to refer to a human being.

Hence, D is the best answer choice.

To understand the concept of "Simple Tenses" on GMAT, you may want to watch the following video (~2 minutes):



To understand the concept of "Comma Plus Present Participle for Cause-Effect Relationship", you may want to watch the following video (~2 minutes):



All the best!
Experts' Global Team

Many thanks DmitryFarber for the detailed explanation.

One more query please -
In option C
a. If " ," is removed after volunteers then will it option be correct?
b. In this option , can "had resumed nesting or investigating " considered parallel.
If not please please explain the error.

I have rewritten the sentence BELOW with the two points mentioned above.

A team of researchers reported that five endangered birds species had resumed nesting or investigating nesting boxes, erected by volunteers ferried out to the island last month.

why can't C be the answer? I really don't get it after seeing the explanations posted above. Explaining answer C in more dtail would be appreciated. thank you

gmatlbs, I hope my response above addresses your concerns, too. I should add that the comma before "erected" is incorrect, too. Since "erected by volunteers" modifies the preceding noun, there's no need for a comma here, and its use only adds confusion as to what we're trying to modify.

A team of researchers reported that five endangered birds species had resumed nesting or investigated nesting boxes erected by volunteers having been ferried out to the island last month.

(a) investigated nesting boxes erected by volunteers having been =>

having been ferried out ----refers to volunteers, so wrong.

(b) begun investigating nesting boxes erected by volunteers, being ==> being refers to bird species. ferried out should refer to boxes as done in C properly.


(c) investigating nesting boxes, erected by volunteers,
ferried out refers to "volunteer" so wrong.

(d) were investigating nesting boxes erected by volunteers

"were" is also wrong. First sentence is in past perfect. past tense in sentence doesnt make sense here.
having been ferried out ----refers to volunteers, so wrong.

(e) investigate nesting boxes erected by volunteers, which

which ----refers to volunteers, so wrong.

I dont understand why C is wrong and Not D.

abrakadabra21, there is a shift in D from past perfect to the simple past. The birds either had already resumed nesting or were currently investigating nesting boxes.

Also, I'm not sure what you mean about the modifier referring to volunteers. The correct meaning is that the volunteers were ferried out, and that's what most of the choices (including D) convey. The "having been" phrase you describe does not appear in D.

DmitryFarber


I had difficulty in understanding the meaning of correct option choice D.

birds species had resumed nesting... Past Perfect

or

birds species were investigating nesting boxes ... Past Continuous

How the usage of Past perfect is justified in above case. I understand past perfect is used to show the sequencing of two events occurred in past.

First Event : Past Perfect ; Second Event : Simple past

Since there was no event expressed in Simple past, I ruled out this option.

Is it correct to use the Past perfect with past continuous to express sequencing of two events?

Kindly clarify.

Hi Sahil, your understanding on Past Perfect is perfect .

The two events are:

(i) A team of researchers reported
(ii) Five endangered birds species had resumed nesting

Since (ii) happened earlier, it is expressed as past perfect, while (i) happened later and hence, is expressed in simple past.

p.s. Our book EducationAisle Sentence Correction Nirvana discusses Past perfect tense, its application and examples in significant detail. If someone is interested, PM me your email-id, I can mail the corresponding section.

I like to draw a time line. So that I know the first verb is going to be the one with that requires past perfect... drawing a line and sequencing from left to right really eliminates confusion for me.

Farrell Dyan Hehn, MBA
Admissions Consultant & Verbal Strategist MBAPrepCoach.com

I have to disagree with you here. By definition, the use of past perfect is correct when there are two RELATED events that happened in different points of time in the past and when there are no indicators of time present such as "before" "after"...

In this case, I believe the two events in comparison are :
1st event: had resumed nesting
2nd event: were investigating nesting boxes.

Thus, the meaning of the sentence is the researchers reported that either birds had already begun nesting (even without the help of nesting boxes) or they were investigating the nesting boxes delivered by the volunteers.

GMATNinjaTwo daagh
please explain your analysis on this question.... i am not able to get the hang of this

saurabh

Generally, it is understood that the birds have the habit of investigating alien nest boxes including those imported from outside before they use it for nesting. This is a caution they exercise to ensure that they do not fall into some kind of a setup made by others intending to take away their offsprings.

That aside, now let's get into the brass tacks of this problem.

a. volunteers having been ferried -- means 'volunteers were ferried' but not the nest boxes.

B. get rid of this choice using the useless word 'being ' used as a modifier of boxes. The comma before 'being' does erase one error but the modifier spoils the show. ( I am calling the participle useless because it has no use in the context.)

C. is a nice choice since 'nesting or investigating' is an object of (we may call it a gerund) the verb 'had resumed'

d. The problem of volunteers ferried out as we saw in 'a'

e. The instantly visible error is that the word 'which' means wrongly the volunteers. In addition, the present tense verb investigate isn't in sync with the general past tense of the clause

HTH

Sorry missed this post earlier.

Since reporting is about nesting, this makes the events related. At the timing of reporting, following were the two events:
i) five endangered birds species had resumed nesting (before the reporting happened and so, is expressed as past perfect)
ii) five endangered birds species were investigating nesting boxes erected by volunteers (at the time of reporting and hence, expressed as past continuous)

This is definitely not true. There are umpteen examples in OG where the correct option uses Past perfect, despite the usage of before/after. For example

The personal income tax did not become permanent in the United States until the First World War; before that time the federal government had depended on tariffs as its main source of revenue.

Hi saurabh9gupta, while daagh sir has explained the answer choices, I would like to re-emphasize why option C is incorrect.

Option C reads:

A team of researchers reported that five endangered birds species had resumed nesting or investigating nesting boxes, erected by volunteers, ferried out to the island last month.

So, in C, parallelism is between nesting and investigating. Hence, the meaning that is getting conveyed in C is that five endangered birds species had resumed:
i) nesting or
ii) investigating nesting boxes

In other words, C conveys that five endangered birds species had resumed investigating nesting boxes.

This is an absurd meaning that birds species had resumed investigating nesting boxes; this would mean that birds species earlier used to investigate nesting boxes, stopped investigating nesting boxes in the middle, and then again resumed investigating nesting boxes. Doesn't make sense!

The most logical meaning is that five endangered birds species:
i) had resumed nesting or
ii) were investigating nesting boxes

This parallelism (between had resumed and were, both verbs) is coming out in D. So, D logically conveys that:
i) five endangered birds species had resumed nesting OR
ii) five endangered birds species were investigating nesting boxes

Why is it necessary that volunteers have to build boxes on the island?
Isn't it equally logical that volunteers build those boxes on MAINLAND and then ship them to island?

It'd help if you could let us know how you read this sentence.

A team of researchers reported that five endangered birds species had resumed nesting or were investigating nesting boxes erected by volunteers ferried out to the island last month.

The two verbs here (had resumed and were investigating) are parallel. Ignore erected by (modifier for nesting boxes) and ferried (modifier for volunteers). Also, don't try to apply "tense parallelism". Verbs may or may not have the same tense. It's a meaning call, and the meaning here is that there were two types of birds (bird species): (a) ones that had already resumed nesting and (b) ones that were investigating the nesting boxes left by volunteers.