( ( Each comet ) ( ( is ( trailed ( by ( streams ( of ( dust particles ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT Each) (NN comet)) (VP (VBZ is) (VP (VBN trailed) (PP (IN by) (NP (NP (NNP streams)) (PP (IN of) (NP (NN dust) (NNS particles))))))) (. .)))
Each comet is trailed by streams of dust particles.
(ROOT (S (NP (JJ Comet) (NNS tails)) (VP (ADVP (RB always)) (VBP point) (PRT (RP away)) (PP (IN from) (NP (NP (DT the) (NN sun)) (PP (RB instead) (IN of) (S (VP (VBG trailing) (PP (IN behind) (NP (DT the) (ADJP (JJ comet) (PP (IN because) (NP (NN dust) (NNS particles)))) (NN recoil))))))))) (. .)))