Assertion: natural gas | /r/HasProperty | popular
Facets:
value: as a vehicle fuel
type: MANNER
value: increasingly
type: DEGREE
Source sentences:
text: Natural gas, which has been used to fuel vehicles since the 1930's, is increasingly popular as a vehicle fuel.
text: Natural gas is also a popular choice of fuel, as it’s less expensive and less polluting compare to coal and crude oil.