capnx wrote:when you have adj/adv that can indicate a time period that is before a specific time in the past, ie: after, before, since, prior, until... pay special attention because they signal two different time periods with one specifically ocurring before another; and if the reference time period is in the past tense (either in the main clause or modifying clause), the period that's before the past must be in past perfect.

We all went out to celebrate after she had completed the race.
Before he arrived, we had already finished the project.

Hi Capnx ..

Thanks

But u too are using ARRIVED which is SIMPLE PAST...
My query is can we use HAD in a sentence (of course with a participle ) withOUT a simple past (as shown in jane example above )..

Before he arrived, we had already finished the project.

So as long as the meaning requires that one action occurs before another that clearly happend in the past, use past perfect