( Therefore ( ( a ( negative ( test result ) ) ) ( ( ( can really ) ( be positive ) ) . ) ) )
(ROOT (S (ADVP (RB Therefore)) (NP (DT a) (JJ negative) (NN test) (NN result)) (VP (MD can) (ADVP (RB really)) (VP (VB be) (ADJP (JJ positive)))) (. .)))
Therefore a negative test result can really be positive.
(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))))))))))) (. .)))