Dear Friends,
Here is a detailed explanation to this question-
noboru wrote:
In a previous design, the weight of the discus used in track competition is concentrated in a metal center, but now it is lined with lead around the perimeter, thereby improving stability in flight and resulting in longer throws.
(A) In a previous design, the weight of the discus used in track competition is concentrated in a metal center, but now it is
(B) According to a previous design, the weight of the discus used in track competition was concentrated in a metal center, but now it is
(C) Once designed with its weight concentrated in a metal center, the discus used in track competition is now
(D) The discus used in track competition, once designed with its weight concentrated in a metal center, but now
(E) The discus used in track competition was once designed having its weight concentrated in a metal center and now
Meaning is crucial to solving this problem:Understanding the intended meaning is key to solving this question; the intended core meaning of this sentence is that the discus used in track competition was once designed with its weight concentrated in a metal center, but now it is lined with lead around the perimeter.
Concepts tested here: Meaing + Tenses + Verb Forms + Awkwardness/Redundancy• The simple past tense is used to refer to events that concluded in the past.
• The simple present tense is to indicate actions taking place in the current time frame, indicate habitual actions, state universal truths, and convey information that is permanent in nature.
A: This answer choice incorrectly uses the simple present tense verb "is" to refer to an event that concluded in the past; please remember, the simple past tense is used to refer to events that concluded in the past, and the simple present tense is only used to indicate actions taking place in the current time frame, indicate habitual actions, state universal truths, and convey information that is permanent in nature. Further, Option A suffers from pronoun ambiguity, as it is unclear whether "it" refers to "discus" or "metal center". Additionally, Option A uses the needlessly wordy construction "In a previous design", leading to awkwardness and redundancy.
B: This answer choice suffers from pronoun ambiguity, as it is unclear whether "it" refers to "discus" or "metal center". Further, Option B uses the needlessly wordy construction "According to a previous design", leading to awkwardness and redundancy.
C: Correct. This answer choice correctly acts upon the independent noun "the discus" with the active verb phrase "is now lined" to form a complete thought, leading to a complete sentence. Further Option C uses the phrase "Once designed with...metal center" to modify "the discus", conveying the intended meaning - that the discus used in track competition used to be designed with its weight concentrated in a metal center, but now it is lined with lead around the perimeter, instead. Additionally, Option C avoids the issue of pronoun ambiguity, seen in Options A and B, as it employs no pronouns. Moreover, Option C correctly uses the simple present tense verb "is now lined" to refer to information that is permanent in nature and avoids the tense error seen in Option A, as it uses the noun modifier "Once designed" rather than an active verb. Besides, Option C is free of any awkwardness or redundancy.
D: This answer choice fails to form a complete sentence; as "once designed" and "now lined" are both noun modifiers, there is no active verb to act upon the subject noun "The discus".
E: This answer choice alters the meaning of the sentence through the phrase "and lined"; the use of "and" incorrectly implies that the discus used in track competition was once designed with its weight concentrated in a metal center, and is now is lined with lead around the perimeter
as well; the intended meaning is that the discus used in track competition was once designed with its weight concentrated in a metal center, but now it is lined with lead around the perimeter,
instead. Further, Option E incorrectly uses the past participle ("lined" in this sentence) to refer to information that is permanent in nature; please remember, information that is permanent in nature is best coveted through the simple present tense.
Hence, C is the best answer choice.To understand the concept of "Simple Tenses" on GMAT, you may want to watch the following video (~1 minute):
All the best!
Experts' Global Team