Assertion: natural gas | /r/ObjectUse | used by the chinese
Facets:
value: in about 500 bc
type: TEMPORAL
Source sentences:
text: Natural gas was first used by the Chinese in about 500 BC (possibly even 1000 BC).
text: Natural gas is believed to have been first discovered and used by the Chinese, perhaps as early as 1000 B.C. Shallow stores of natural gas were released from just beneath the ground and piped short distances to be used as a fuel source.