( ( For ( plane mirrors ) ) ( , ( ( virtual images ) ( ( are formed ) . ) ) ) )
(ROOT (S (PP (IN For) (NP (NN plane) (NNS mirrors))) (, ,) (NP (JJ virtual) (NNS images)) (VP (VBP are) (VP (VBN formed))) (. .)))
For plane mirrors, virtual images are formed.
(ROOT (S (NP (DT A) (NN plane) (NN mirror)) (VP (VP (VBZ has) (NP (DT a) (ADJP (JJ flat) (JJ reflective)) (NN surface))) (CC and) (VP (VBZ forms) (NP (RB only) (JJ virtual) (NNS images)))) (. .)))