Assertion: metro's construction | /r/CapableOf | begin after a groundbreaking ceremony
Facets:
value: on december
type: TEMPORAL
Source sentences:
text: Construction began after a groundbreaking ceremony on December 9, 1969, when Secretary of Transportation John A. Volpe, District Mayor Walter Washington, and Maryland Governor Marvin Mandel tossed the first spade of dirt at Judiciary Square.