its implying past perfect because consider the following situation-
here with in 20 years means that something happened before the completion of 20 years therefore, past perfect has been used
From Kaplan Test
This topic has expert replies
Source: Beat The GMAT — Sentence Correction |
-
aspirant2011
- Legendary Member
- Posts: 1574
- Joined: Fri Jan 28, 2011 2:52 am
- Thanked: 88 times
- Followed by:13 members












