( ( A millibar ) ( ( is ( used ( to ( measure ( air pressure ) ) ) ) ) . ) )
(ROOT (S (NP (DT A) (NN millibar)) (VP (VBZ is) (VP (VBN used) (S (VP (TO to) (VP (VB measure) (NP (NN air) (NN pressure))))))) (. .)))
A millibar is used to measure air pressure.
(ROOT (S (NP (NNP Millibar)) (VP (VBZ is) (NP (NP (DT the) (NN unit)) (VP (VBN used) (S (VP (TO to) (VP (VB measure) (NP (NN air) (NN pressure)))))))) (. .)))