[time] when vs at which : GMAT Sentence Correction (SC)
Check GMAT Club Decision Tracker for the Latest School Decision Releases https://gmatclub.com/AppTrack

 It is currently 19 Feb 2017, 12:23

### GMAT Club Daily Prep

#### Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# [time] when vs at which

Author Message
TAGS:

### Hide Tags

Intern
Joined: 18 Apr 2009
Posts: 9
Followers: 0

Kudos [?]: 3 [0], given: 1

[time] when vs at which [#permalink]

### Show Tags

25 Apr 2009, 08:31
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions

### HideShow timer Statistics

What is the difference between when and at which in this case ?
Both in this case describe the time, the ealiest date.

Scientist have dated sharp-edged flakes of stone to between 2.52 and 2.6 million years ago, pushing back by more than 150,000 years the earliest date at which humans are known to have made stone tools (Correct)

Scientist have dated sharp-edged flakes of stone to between 2.52 and 2.6 million years ago, pushing back by more than 150,000 years the earliest date when humans are known to have made stone tools (is this wrong?)
If you have any questions
New!
Senior Manager
Joined: 10 Dec 2008
Posts: 482
Location: United States
GMAT 1: 760 Q49 V44
GPA: 3.9
Followers: 40

Kudos [?]: 200 [0], given: 12

Re: [time] when vs at which [#permalink]

### Show Tags

12 May 2009, 16:11
An informal definition/general rule of thumb is that "when" emphasizes the period of time in which something occurs and not the time period itself, whereas "at which" refers to the specific point in time, but not necessary the actions occuring in that period.

e.g.

Remember the time when we went to the store? <- refers to the time when something happens, namely the period when you are at the store, emphasis on the action happening in the tore

The time at which you will go to the store is 9:00pm. <- refers specifically to the time you must go to the store

The second sentence - the earliest date when humans are known - sounds a bit odd
Re: [time] when vs at which   [#permalink] 12 May 2009, 16:11
Similar topics Replies Last post
Similar
Topics:
2 IF Vs When in GMAT SC 0 06 Jul 2015, 12:51
1 Sulfur dioxide, which smells like rotten eggs is formed (From Vs When) 1 18 Nov 2014, 09:14
through vs by ...when to use which 0 28 Jun 2014, 17:07
1 that vs which 7 15 Sep 2010, 02:07
which vs. that 5 13 Jan 2010, 12:33
Display posts from previous: Sort by