Assertion: drummer's role | /r/CapableOf | evolve to small extent
Facets:
value: in the bebop period
type: TEMPORAL
value: in the swing era
type: TEMPORAL
Source sentences:
text: To a small extent in the swing era, but most strongly in the bebop period, the role of the drummer evolved from an almost purely time-keeping position to that of a member of the interactive musical ensemble.