Two of them saw Thorn coming.
( ( Two ( of them ) ) ( ( saw ( Thorn coming ) ) . ) )
(ROOT (S (NP (NP (CD Two)) (PP (IN of) (NP (PRP them)))) (VP (VBD saw) (NP (NNP Thorn) (VBG coming))) (. .)))
Thorn was seen coming by two of them.
( Thorn ( ( was ( seen ( coming ( by ( two ( of them ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Thorn)) (VP (VBD was) (VP (VBN seen) (S (VP (VBG coming) (PP (IN by) (NP (NP (CD two)) (PP (IN of) (NP (PRP them))))))))) (. .)))