AS YOU LIKE IT - At the Folger through July 15 (previews through this Sunday).

Periods in which plays are set being now a matter of as you like it, rather than when they were written or a time designated by the playwright, there is no reason that the Folger Theater's "As You Like It" shouldnot take place in Regency England. Or perhaps it's Napoleonic France. Bosoms, in any case, are being worn high.

The need seems to have been felt for an excuse to have grown people running abour pinning love notes on trees and pledging their lifelong devotion to strangers. Foppishness would explain a lot-too much, perhaps, as it suggests momentary poses. The Jane Austen look could represent archness, but not giddiness. The Frangonard idea accounts for everyone's being outdoors, but not for their playing for keeps.

But while Shakespearean comedy is often the richer for inventively silly stage business, one doesn't need to wander for centuries looking for help.

This production is fortunate to have two gifted Shakespearean comedians, Glynis Bell as Celia, which is not ordinarily a choice part, and David Cromwell as Touchstone, which is. In both, it's the quality of paying close attention to their own peculiar feelings and the antics of others, of seeming to be always amazedly pondering what exactly is going on here, that makes one relish their delicious lines and underscores those of others to whom they are reacting.

The rest is gravy, and gravy can enhance or smother. When Celia embellishes her role by quietly polishing off a wicker wine bottle and crossing herself with it when things go too far, a good performanc is embellished. When Touchstone is supplied with the built-in giggle of having his lady love be in an advanced state of pregnancy without his noticing it, a good performance is belittled.

Otherwise, this is a good but not memorable version of the comedy, at least judging from the first of this week's previews. (The play officially opens on Monday.) Helen Carey and Michael Tolaydo are an enthusiastic Rosalind and Orlando, Leonardo Cimino occasionally makes the banished duke look like the Mad Hatter, and some tiny parts as country folk, played by Ray Aranha, Brian Corrigan and Franchelle Stewart Dorn, Are charming.

In each case, it's spirited earnestness, rather than gimmicks, that does it.