Assertion: preview | /r/CapableOf | start as common form of advertisement
Facets:
value: in the late 2000s
type: TEMPORAL
Source sentences:
text: While not initially prevalent in television, TV show trailers started as a common form of advertisement in the late 2000s.
text: While not initially prevalent in television, TV show trailers started as a common form of advertisement in the late 2000s.