I said the Boston Ballet had improved last year, and then I took it back. They looked willing, but there were lapses. In last week's performance, dubbed ''Greatest Hits,'' the promise was there, but there was also strength behind it.
''Madrilene Pas de Deux,'' to melodramatic Spanish music from Massenet's ''Le Cid,'' was one of those frothy, pouncing romps Bruce Wells keeps making for Laura Young, longtime prima ballerina of the company. The wonderful thing about it was that I didn't recognize Laura Young. It wasn't just the curly wig she wore with the standard wicked-senorita dress. She used to look strained when leaping. Now, she seems released. Her head is high, and she's bouyant, topping off the unerring precision she has always shown on toe with a new fluidity.
Violette Verdy's ''Bach: Suite 3'' has brightened as if it had been scoured. The corps is well-drilled. Marie-Christine Mouis and Jean-Philippe Halnaut moved wonderfully together through the ballet's gooey pas de deux. Even though it looked as if Halnaut was only there to rush around the stage catching her in many stages of one long, elegant swoon, Mouis was really hard at work, so you felt gravity didn't really have too much to do with her descent. Everyone seems to have been hard at work.