Assertion: migration | /r/HasProperty | known and accepted fact
Facets:
value: well
type: DEGREE
Source sentences:
text: The migration of birds is now a well known and accepted fact and we find it hard to understand how such fanciful ideas could ever have been believed.
text: The migration of birds is now a well known and accepted fact and we find it hard to understand how such fanciful ideas could ever have been believed.