As a result of a new technique that combines light from two

1. Need clarification on Verb-ed and Verb-ing
2. as a compact structure has to be parallel to measuring ? If so, shouldn't there be another----- as a ... ??

Here is a post on past and present participles: https://www.gmatclub.com/forum/veritas-prep-resource-links-no-longer-available-399979.html#/2014/1 ... -the-gmat/

As a result of a new technique that combines light from two powerful telescopes, astronomers have recently identified the torus at the center of the active galactic nucleus NGC 1068 as a warm compact structure composed of dust and gas and measuring several light-years across.

a. measuring: correct
b. measures: not parallel with "composed"
c. measured : : Meaning error
d. it measured : not parallel with "composed"
e. is measuring : not parallel with "composed"

should't it be "measures" since it's a general fast about the nucleus?

sampriya :- "measures" is a verb whereas "composed and measuring" are noun modifiers modifying warm compact structure. You need parallel stuff with "and" marker. First verb that measures goes with would be astronomers have found and as you see they don't measure several light years

Infact, b), c) and e) all use verbs and thus can not be parallel to "composed" and d) uses a complete clause

In A) measuring is a modifier modifying a warm compact structure. "composed" (Verb-ed modifier) and measuring ("Verb-ing" modifier touching noun act as a noun modifier) are parallel to each other.

Hi sampriya,

To add to shameekv1989 's reply, measuring is not a complete verb (it's a modifier). Think of it as a shorter way of saying that measures. In other words, this usage is not inconsistent with your point.

We found an artifact measuring 10 feet...
is a shorter way of saying
We found an artifact that measures 10 feet...

This works for some verbs, like measure, but it will not work for all.

You can also try the official question that this question is based on.

Hi

Here is something you can use in future applications...

If we replace “measuring” with measures, we will get:

Astronomers.. identified the torus… as a… structure
composed of dust
and measures several light-years across.

Now if measures is a verb, then ask yourself who is the doer of this verb– Who/What measures?

Do the astronomers measure, does the nucleus measure anything?
NO.
Therefore, if “measures” does not have a subject/doer, it cannot be the verb/correct fit here.

In fact whenever in doubt about a word being a verb, ask the question “Who+verb?” or “What+verb?”(do not add any helping verb while asking this question)

For e.g.,
The car abandoned near the school is badly damaged.

Is “abandoned” a verb?
Ask – Who/What abandoned? Obviously the car did not abandon anything. Since the subject “car” is not the answer to this question, “abandoned” is not a verb but a modifier.

If the answer elicits the correct logical subject, then the word is a verb.

Hope this helps

Hi, I do not understand why C. Measured is wrong. Isn't measured here an adjective that modifies the subject.

As a result of a new technique that combines light from two powerful telescopes, astronomers have recently identified the torus at the center of the active galactic nucleus NGC 1068 as a warm compact structure composed of dust and gas and measuring several light-years across.

a. measuring
b. measures
c. measured
d. it measured
e. is measuring

‘Measured’ in C is not an adjectival modifier modifying the previous noun compact structure. The phrase several light-years is a synonym of some distance. For the sake of clarity, let us call it some two million miles. The implied meaning is that the structure measured (V2 verb) some 2 million miles. On the contrary, ‘composed of’ is a past participle (V3 form). In the given choices, also all other words after ‘and', except in A are present tense or past tense verbs and hence are not parallel.

Official Explanation:
The word "structure" is modified by two participial phrases: "composed of dust and gas" and "measuring several light-years across." The past participle is correct for the phrase "composed of" or "made of," since the composition was done in the past. For the second phrase, the present participle "measuring" is correct, since this measurement exists in the present.
Scan and Group the Answer Choices:
(B), (C), (D), and (E) use "measures," "measured," and "is measuring" as verbs, not as participles, and hence do not supply the required parallel construction. Since "composed of" functions as a participial adjective, "measuring" must also.
Eliminate Wrong Answer Choices:
A common mistake is to choose (C), thinking that parallel structure dictates the choice of "composed" to create parallel structure with "measured." While parallel structure often works this way, in this case, parallel structure dictates not that the verb forms should be the same but that both verbs should be used as participial adjectives. And the correct participial adjectives here are "composed" (of dust and gas) and "measuring" (several light-years across).
(D) also uses the redundant "it," and (E) is unnecessarily wordy.
(A) is correct.
TAKEAWAY: Invest time in analyzing the sentence to save time evaluating the choices.

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