A little bit of knowledge is a dangerous thing, but a whole lot of smarts can really screw you up. Just look at Frank, the English tutor in Willy Russell’s play “Educating Rita,” which opened over the weekend at Acadia Repertory Theatre in Somesville.

Frank is a fine figure of a man — well-read, intelligent, talented as a poet — but he’s so bored with his life and frozen in his own sense of inadequacy that he is both arrogant and drunk through a good portion of each day.

He learns a thing or two when Rita, a working-class hairdresser, bursts through his office door on a quest for knowledge. The fervor of her intellectual hunger is matched only by her naivete. She’s smart all right, but she has a long way to go before she’s educated. As much as Frank tries to reject Rita, as much as he can’t suppress a grin at the unique elan behind her punk hair and stiletto heels, he finally can’t resist her, and becomes as attached to her moxie as she is to her books.

Their relationship grows through a series of episodes that take place in Frank’s university office somewhere in England. In each scene, Frank becomes more disillusioned about himself and Rita becomes more confident about herself. Frank also becomes more drunk, and Rita more highbrow. Neither one becomes more likable in this transformation, but their educations are not over until they face some pomp and circumstance about their essential selves.

“Educating Rita” is a two-person show, popularized in 1983 with a film version staring Michael Caine and Julie Walters (who was in the original stage version). It was a hit because it combined good humor with a good lesson. In Ken Stack’s production, the entertainment value and the poignancy factor high, too, thanks to the untiring effort and skill of actors Ted Cancila and Kathleen Lake.

Each is a veteran of the Acadia Rep stage, which almost always assures that an actor has some solid ability. It’s to Stack’s credit that he knows a good thing when he sees it, and keeps it around when it’s working. Seldom are there casting problems in this company, and “Educating Rita” attests to that yet again.

As Frank, Cancila turns in a performance that is funny and frightening, whether the scene calls for him to be appallingly stuffy or pathetically sloshed. When he puts his academic nose in the air, it’s way up there, and when he’s toasted, he’s twice as supercilious.

Lake, as Rita, gives new meaning to the word brainstorm. She’s spontaneous, tough and confrontative in the beginning, and progresses to a good little schoolgirl who has to learn some lessons that can’t be found in books. Lake makes the transition smoothly, plus manages some tricky costume changes. She never quite gets comfortable with the cigarettes she has to smoke or the various handbags she totes. But these are niggling details, and the strength of her performance lies with the larger issues of her character’s vehemence.

The backstage and technical teams have their work cut out for them on this one, which has 15 scenes and many costume changes. Stage manager Laura Anne Hodos does a superb job with the props. Jodie Osgood’s versatile costumes move a bit too drastically from hot to homely, but it’s fun to watch the changes. And Jonathan Ferreira’s technical direction keeps pace with the whirling action.

“Educating Rita” will be performed 8:15 p.m. Thursday-Saturday and 2 p.m. Sunday through July 14 at Acadia Repertory Theatre in Somesville. For tickets, call 244-7260.