A calendar stick carved centuries ago by the Winnebago tribe may pro

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 intended meaning of this sentence is that a “calendar stick” carved centuries ago by the Winnebago tribe may provide the first evidence that the North American Indians developed advanced full-year calendars that were on systematic astronomical observation.

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

• The simple past tense is used to refer to actions that concluded in the past.
• The present perfect tense (marked by the use of the helping verb “has/have”) is used to describe events that concluded in the past but continue to affect the present.

A: This answer choice incorrectly uses the present perfect tense verb “have developed” to refer to an action that concluded in the past; please remember, the present perfect tense (marked by the use of the helping verb “has/have”) is used to describe events that concluded in the past but continue to affect the present. Further, Option A incorrectly uses the present participle (“verb+ing”- “basing” in this sentence) to refer to an action that concluded in the past; please remember, the simple past tense is used to refer to actions that concluded in the past.

B: This answer choice alters the meaning of the sentence through the phrase “evidence of the North American Indians”; the construction of this phrase illogically suggests that the “calendar stick” is strong evidence of the existence of the North American Indians; the intended meaning is that the “calendar stick” is strong evidence of the fact that the North American Indians developed advanced full-year calendars that were on systematic astronomical observation. Further, Option B incorrectly uses the present perfect tense verb “have developed” to refer to an action that concluded in the past; please remember, the simple past tense is used to refer to events that concluded in the past, and the present perfect tense (marked by the use of the helping verb “has/have”) is used to describe events that concluded in the past but continue to affect the present.

C: This answer choice incorrectly uses present participle (“verb+ing”- “basing” in this sentence) to refer to an action that concluded in the past; please remember, the simple past tense is used to refer to actions that concluded in the past.

D: This answer choice alters the meaning of the sentence through the phrase “evidence of the North American Indians and their development…”; the construction of this phrase illogically suggests that the “calendar stick” is strong evidence of the existence of the North American Indians; the intended meaning is that the “calendar stick” is strong evidence of the fact that the North American Indians developed advanced full-year calendars that were on systematic astronomical observation.

E: Correct. This answer choice uses the phrase “evidence that the North American Indians developed…”, conveying the intended meaning of the sentence- that the “calendar stick” is strong evidence of the fact that the North American Indians developed advanced full-year calendars that were on systematic astronomical observation. Further, Option E correctly uses the simple past tense verb “developed” and the past participle (“based” in this sentence) to refer to actions that concluded in the past.

To understand the concept of "Simple Tenses" on GMAT, you may want to watch the following video (~1 minute):



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



All the best!
Experts' Global Team
Hence, E is the best answer choice.