Wolf Trap's annual showpiece recital for its 20 summer intern opera singers was presented yesterday.

These events, called "Future Stars in Concert," are almost inevitably bits and pieces of opera songs, rather than performances of display pieces.

It's just impossible to squeeze so many singers into little more than two hours and show every performer to fair advantage -- just as it is impossible to review all of them with certainty based on five-minute snatches of music. Some are, no doubt, better singers than they sounded yesterday, and some might be worse.

There was no single standout. And though several singers were clearly outstanding, there was no line of demarcation between the best and the less-than-best.

Some stood out in part because they chose the right work. Diane Kesling was exactly on the mark in finishing the program with Richard Strauss' "Sein wir wieder gut" from "Ariadne auf Naxos." It is, of course, a magnificent work and it beautifully showed her interpretive talent as well as her mid- and high-mezzo range. The orchestra, under Richard Woitach, sounded particularly stirred up.

And just before that, bass Robert Keefe sounded fine in Aleko's cavatina from Rachmaninoff's "Aleko."

Other performers made bad choices. For instance, Alexandra Althoff should never have taken on the rigorous final scene from act one of Verdi's "La Traviata." You take that work on at your own risk.

Several others were especially good: baritone Ronald Madden and Prince Yeletsky's aria from Tchaikovsky's "The Queen of Spain"; soprano Virginia Boomer in "Stridono Lassu" from Leon Cavalo's "I Pagliacci"; mezzo Patricia Schuman in "Non piu mesta" from Rossini's "Cenerentola"; bass Bruce Kramer in "La Calunia" from "The Barber of Seville"; and soprano Ruth Jacobson in "Oh quante volte" from Bellini's "I Capuletti ed i Montecchi."