He could make quite an issue out of the need to determine the characteristic impedance of their sky.
( He ( ( could ( ( ( make ( quite ( an issue ) ) ) out ) ( of ( the ( need ( to ( determine ( ( the ( characteristic impedance ) ) ( of ( their sky ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP He)) (VP (MD could) (VP (VB make) (NP (PDT quite) (DT an) (NN issue)) (PRT (RP out)) (PP (IN of) (NP (DT the) (NN need) (S (VP (TO to) (VP (VB determine) (NP (NP (DT the) (JJ characteristic) (NN impedance)) (PP (IN of) (NP (PRP$ their) (NN sky))))))))))) (. .)))
He could have made an issue about the need to determine the impedance of the sky.
( He ( ( could ( have ( ( made ( an issue ) ) ( about ( the ( need ( to ( determine ( ( the impedance ) ( of ( the sky ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP He)) (VP (MD could) (VP (VB have) (VP (VBN made) (NP (DT an) (NN issue)) (PP (IN about) (NP (DT the) (NN need) (S (VP (TO to) (VP (VB determine) (NP (NP (DT the) (NN impedance)) (PP (IN of) (NP (DT the) (NN sky)))))))))))) (. .)))