The phrase 'had participated at' is correct and usable in written English.
You would use this phrase when talking about an event or activity that happened in the past and was completed. For example: Sarah had participated at the science fair, where she showcased her experiment on the chemical properties of water.
Eligible survey participants at the 2-year follow-up (T2) were students who had participated at T1. Multiple approaches were used to contact the adolescents at follow-up.
So did Massachusetts and New Jersey, along with the American Lung Association, which had participated at the appeals court level to defend the new clean air standards.
"During the inaugural weekend, they didn't have the capacity to handle all the people who had participated at the highest levels, because there were so many".
They said Mr. Medunjanin had participated at every step of the way, including helping select the sites where they would set off their bombs.
They had participated at a BBC "hackathon" event held in Cape Town in April looking at making BBC audio more accessible to young people.
Patients who were lost to follow-up at the 6-month visit but who had participated at the 3-month visit were included in the 3-month postoperative analysis.
However, while every alliance member voted for Libya mission, less than half have participated at all, and fewer than a third have been willing to participate in the strike mission.
"While every alliance member voted for the Libya mission, less than half have participated at all, and fewer than a third have been willing to participate in the strike mission," Mr. Gates said, referring to NATO's North Atlantic Council and not the United Nations, where Germany abstained.
It is not the first time Australians have participated at the song contest.
Results Thirty-one medical residents (17 anaesthesiologists, 14 paediatricians) and 5 fellows (1 anaesthesiologist and 4 paediatricians) have participated at this 1 day course training.
