Subject	plane mirror
Predicate	form
Object	virtual image
Modality	Modality Occurrences always 2 only 1
Polarity	POSITIVE
Plausibility	0.8769
Neighborhood Sigma	0.8769
Local Sigma	1.0000
Example Sentences	Sentence Occurrences Source plane mirrors form virtual images 3 Google Autocomplete a plane mirror always form a virtual image 2 Google Autocomplete plane mirrors and convex mirrors form only virtual images 1 Answers.com Questions plane mirrors form a virtual image 1 Answers.com Questions