( ( ( ( ( Equipotential ( ( lines and ) surfaces ) ) , ) and ) ( field lines ) ) . )
(ROOT (S (VP (VP (VB Equipotential) (NP (NNS lines) (CC and) (NNS surfaces))) (, ,) (CC and) (VP (VB field) (NP (NNS lines)))) (. .)))
Equipotential lines and surfaces, and field lines.
(ROOT (S (SBAR (IN Since) (S (NP (DT the) (JJ electric) (NN field) (NNS lines)) (VP (VBP point) (ADVP (RB radially)) (ADVP (RB away) (PP (IN from) (NP (DT the) (NN charge))))))) (, ,) (NP (PRP they)) (VP (VBP are) (ADJP (JJ perpendicular) (S (VP (TO to) (VP (VB equipotential) (NP (NNS lines))))))) (. .)))