( ( A meter ) ( ( is ( ( defined today ) ( as ( ( the distance ) ( ( a ( light particle ) ) ( travels ( in ( ( ( one 299,792,458 ) th ) ( of ( a second ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT A) (NN meter)) (VP (VBZ is) (VP (VBN defined) (NP (NN today)) (PP (IN as) (NP (NP (DT the) (NN distance)) (SBAR (S (NP (DT a) (JJ light) (NN particle)) (VP (VBZ travels) (PP (IN in) (NP (NP (QP (CD one) (CD 299,792,458)) (NN th)) (PP (IN of) (NP (DT a) (NN second)))))))))))) (. .)))
A meter is defined today as the distance a light particle travels in one 299,792,458th of a second.
(ROOT (S (NP (JJ Meter) (JJ much) (NN distance)) (VP (MD can) (VP (VB beta) (NP (JJ particles) (NN travel)) (PP (IN through) (NP (NN air))))) (. .)))