Assertion: duck | /r/CapableOf | keep one eye
Facets:
value: often
type: TEMPORAL
value: to watch for predators
type: PURPOSE
Source sentences:
text: The duck at the end of the line will keep one eye open to watch for predators.
text: Ducks sleeping at the end of a line often keep the eye closest to the other ducks closed, while the other eye remains open.