Assertion: natural gas's form | /r/ObjectUse | used by various civilizations
Facets:
value: according to historical records
type: OTHER
value: thousands of years ago
type: TEMPORAL
value: on various continents
type: LOCATION
Source sentences:
text: Some forms of petroleum, coal, and natural gas were used thousands of years ago by various civilizations on various continents, according to historical records and archaeological finds.
text: Some forms of petroleum, coal, and natural gas were used thousands of years ago by various civilizations on various continents, according to historical records and archaeological finds.