( ( In ( a superconductor ) ) ( however ( , ( ( the resistance ) ( ( ( drops abruptly ) ( to ( zero ( when ( ( the material ) ( is ( cooled ( below ( its ( critical temperature ) ) ) ) ) ) ) ) ) ) . ) ) ) ) )
(ROOT (S (PP (IN In) (NP (DT a) (NN superconductor))) (ADVP (RB however)) (, ,) (NP (DT the) (NN resistance)) (VP (VBZ drops) (ADVP (RB abruptly)) (S (VP (TO to) (VP (VB zero) (SBAR (WHADVP (WRB when)) (S (NP (DT the) (NN material)) (VP (VBZ is) (VP (VBN cooled) (PP (IN below) (NP (PRP$ its) (JJ critical) (NN temperature))))))))))) (. .)))
In a superconductor however, the resistance drops abruptly to zero when the material is cooled below its critical temperature.
(ROOT (S (NP (NNS Superconductors)) (VP (VBP are) (NP (NP (NNS materials)) (PP (IN with) (NP (NP (DT a) (NN resistivity)) (PP (IN of) (NP (CD zero))))))) (. .)))