Assertion: great auk's wing | /r/SimilarTo | crescent
Facets:
Source sentences:
text: Many swifts have long swept-back wings which resemble a crescent or boomerang.
text: Many swifts have very long swept-back wings which resemble a crescent or boomerang.
text: Many swifts have long swept-back wings which resemble a crescent or boomerang.