In interviews with us, NEADS personnel expressed considerable confusion over the nature and effect of the order.
( ( In ( interviews ( with us ) ) ) ( , ( ( NEADS personnel ) ( ( ( expressed ( considerable confusion ) ) ( over ( ( the ( ( nature and ) effect ) ) ( of ( the order ) ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN In) (NP (NP (NNS interviews)) (PP (IN with) (NP (PRP us))))) (, ,) (NP (NNP NEADS) (NNS personnel)) (VP (VBD expressed) (NP (JJ considerable) (NN confusion)) (PP (IN over) (NP (NP (DT the) (NN nature) (CC and) (NN effect)) (PP (IN of) (NP (DT the) (NN order)))))) (. .)))
NEADS personnel understood the nature and effect of the order perfectly. 
( ( NEADS personnel ) ( ( ( understood ( ( the ( ( nature and ) effect ) ) ( of ( the order ) ) ) ) perfectly ) . ) )
(ROOT (S (NP (NNP NEADS) (NNS personnel)) (VP (VBD understood) (NP (NP (DT the) (NN nature) (CC and) (NN effect)) (PP (IN of) (NP (DT the) (NN order)))) (ADVP (RB perfectly))) (. .)))