Question

A site once used as an observatory by the Anasazi, ancient pueblo dwellers of New Mexico, has been recently discovered where patterns of light and shadow were employed to establish the precise limits of the positions of the Sun and Moon over a nineteen-year cycle.

Option A
Option B
Option C
Option D
Option E

(This question is from Official Guide. Therefore, because of copyrights, the complete question cannot be copied here. The question can be accessed at GMAT Club)

Solution

Sentence Analysis

A site (Main Subject)
- once used as an observatory (Verb-ed modifier – modifies the main subject)
  - by the Anasazi, (Prepositional Phrase – modifies “used”)
    - ancient pueblo dwellers of New Mexico, (Noun Phrase – modifies “Anasazi”)
has been recently discovered (Main Verb)
where patterns of light and shadow were employed (Relative clause – needs to modify the main subject)
- to establish the precise limits (Infinitive Phrase – modifies “were employed”)
  - of the positions (Prepositional Phrase – modifies “limits”)
    - of the Sun and Moon (Prepositional Phrase – modifies “positions”)
  - over a nineteen-year cycle. (Prepositional Phrase – modifies “positions”)

A site has been recently discovered. The site was once used by the Anasazi as an observatory. At this site, patterns of light and shadow were employed to establish the limits of the positions of the Sun and Moon over a time period.

The relative clause (“where” clause) appears after the verb and is thus incorrectly placed. It needs to appear right after the noun it modifies.

Option Analysis

(A) Incorrect. For the reason stated above.

(B) Incorrect. Here, “where” seems to refer to Anasazi.

- At a recently discovered site (Prepositional Phrase – modifies the main verb “were employed”)
  - once used as an observatory by the Anasazi, (Verb-ed modifier – modifies the main subject)
    - ancient pueblo dwellers of New Mexico, (Noun Phrase – modifies “Anasazi”)
- patterns of light and shadow were employed (Main Clause)
  - to establish the precise limits (Infinitive Phrase – modifies “were employed”)
    - of the positions (Prepositional Phrase – modifies “limits”)
      - of the Sun and Moon (Prepositional Phrase – modifies “positions”)
      - over a nineteen-year cycle (Prepositional Phrase – modifies “positions”)

(D) Incorrect. For the following reasons:

This option doesn’t mention that the site was used as an observatory by the Anasazi
The positioning of the prepositional phrase “at a site” creates confusion as to what it modifies. Given the placement, it can modify cycle, positions, or “were employed”.

(E) Incorrect. For the following reasons:

The use “the site” is incorrect since “that” already refers to the place. Without “the site”, the “that” clause will be fine.
The positioning of the prepositional phrase “at a recently discovered place” creates confusion as to what it modifies. Given the placement, it can modify cycle, positions, or “were employed”.

This solution was created by Anish Passi and Chiranjeev Singh.

If you have any doubts regarding any part of this solution, please feel free to ask in the comments section.

Anish Passi

With over a decade of GMAT training experience, top 1 percentile scores on the CAT and GMAT, Anish is one of the most qualified GMAT coaches in India. He has founded and served as Director in two edu-tech startups in the past. An alumnus of IIM Ahmedabad and McMaster University, Canada, he strongly believes in the right way of learning, and in learning to grow and not just to get a score, an admission or a job. Anish offers private tutoring (online and in-person), and workshops for groups. His sessions are often sprinkled with jokes that only he finds funny (you've been warned). To connect with him, write to him at a@TheGMATCo.com

Karan says:

July 16, 2021 at 9:20 pm

In option C how is “over a nineteen year cycle” modifying “positions”? What question are you asking that it modifies positions?