( ( Insulator ( ( A material ) ( that ( has ( ( a ( high resistance ) ) ( to ( current flow ) ) ) ) ) ) ) . )
(ROOT (S (VP (VB Insulator) (NP (NP (DT A) (NN material)) (SBAR (WHNP (WDT that)) (S (VP (VBZ has) (NP (NP (DT a) (JJ high) (NN resistance)) (PP (TO to) (NP (JJ current) (NN flow))))))))) (. .)))
Insulator    A      material that has a high resistance to current flow.
(ROOT (S (NP (PRP You)) (VP (VBP call) (NP (NP (NNS materials)) (SBAR (WHNP (WDT that)) (S (VP (VBP have) (NP (JJ high) (NN resistance)) (PP (TO to) (NP (JJ electric) (JJ current) (JJ electric) (NNS insulators)))))))) (. .)))