( ( Positive ( and ( negative values ) ) ) ( ( should ( be tested ) ) . ) )
(ROOT (S (NP (JJ Positive) (CC and) (JJ negative) (NNS values)) (VP (MD should) (VP (VB be) (VP (VBN tested)))) (. .)))
Positive and negative values should be tested.
(ROOT (S (NP (PRP We)) (VP (VBP call) (NP (NP (DT an) (JJ incorrect) (NN test) (NN result)) (SBAR (WHNP (WDT that)) (S (VP (MD should) (VP (VB have) (VP (VBN been) (ADJP (JJ positive) (NP (NP (DT a) (-LRB- -LRB-) (NN n) (-RRB- -RRB-)) (ADJP (JJ false) (JJ negative))))))))))) (. .)))