Assertion: helicopter | /r/HasProperty | developed into viable battlefield contributor
Facets:
value: during the days of world war
type: TEMPORAL
Source sentences:
text: While the helicopter was already being developed into a viable battlefield contributor during the days of World War 2 (1939-1945), it was not until the Korean War (1950-1953) that its service was entrenched.
text: While the helicopter was already being developed into a viable battlefield contributor during the days of World War 2 (1939-1945), it was not until the Korean War (1950-1953) that its service was entrenched.