Source: Official Guide for GMAT Review 2016 Sentence Correction; #137

5

By 1999, astronomers had discovered 17 nearby stars

By 1999, astronomers had discovered 17 nearby stars that are orbited by planets about the size of Jupiter.

1 Explanation

1

Adam

We need the past perfect to denote an event that occurred before a specified time in the past, so eliminate (D) and (E). (B) and (C) are unnecessarily wordy. (A) presents the information in the most concise manner.

Sep 1, 2017 • Comment

xiaoyang wu

I am struggling between A and E.
"an event that occurred before a specified time in the past.“
How to confirm above time frame?
Why we can assure that the stated sentence is on the same time frame?

Apr 25, 2020 • Reply

Adam Lyons, Magoosh Tutor

Today is after 1999. So 1999 is in the past. According to the sentence, though, astronomers had discovered 17 nearby stars *before* 1999. So we have an action that took place before a specified time in the past. The discovering took place before 1999. So that's why we need the past perfect.

May 10, 2020 • Reply

Add Your Explanation

You must have a Magoosh account in order to leave an explanation.

Learn More About Magoosh

Official GMAT Material

Official Guide for GMAT Review 2016

Official Guide for the GMAT 2015 14th Ed.

Official Guide for the GMAT 13th Ed.

Nova's GRE Prep

Official Guide for the GMAT 12th Ed.

Revised GRE PDF 2nd Ed.


Section 9.6 Sentence Correction

Improve Your Score

Magoosh GMAT is an affordable online course for studying the GMAT.

Learn More About Magoosh

Share Post

Email

Facebook