Subject	metamorphic rock
Predicate	form
Object	at earth's surface
Modality	Modality Occurrences rarely 1
Polarity	POSITIVE
Plausibility	0.9443
Neighborhood Sigma	0.9443
Local Sigma	1.0000
Example Sentences	Sentence Occurrences Source metamorphic rocks rarely form at earth's surface 1 Google Autocomplete metamorphic rocks form at the earth's surface 1 Google Autocomplete