Assertion: unit's definition | /r/HasProperty | modified since the metre convention
Facets:
value: in 1875
type: TEMPORAL
value: several times
type: TEMPORAL
Source sentences:
text: The definitions of the base units have been modified several times since the Metre Convention in 1875, and new additions of base units have occurred.
text: The definitions of the base units have been modified since the Metre Convention, in 1875.