Assertion: tartar | /r/HasProperty | hard substance
Facets:
value: firmly
type: MANNER
value: very
type: DEGREE
Source sentences:
text: Tartar is a very hard substance, too hard to be brushed off with a toothbrush.
text: Brushing and flossing can remove plaque from which calculus forms; however, once formed, calculus is too hard (firmly attached) to be removed with a toothbrush.