( ( When ( electrons ( ( are not ) ( ( shared equally ) ( in ( a ( covalent bond ) ) ) ) ) ) ) ( , ( ( the molecule ) ( ( is ( described ( as polar ) ) ) . ) ) ) )
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (NNS electrons)) (VP (VBP are) (RB not) (VP (VBN shared) (ADVP (RB equally)) (PP (IN in) (NP (DT a) (JJ covalent) (NN bond))))))) (, ,) (NP (DT the) (NN molecule)) (VP (VBZ is) (VP (VBN described) (PP (IN as) (NP (NNP polar))))) (. .)))
When electrons are not shared equally in a covalent bond, the molecule is described as polar.
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (NNS electrons)) (VP (VBP are) (VP (VBN shared) (ADVP (RB equally)))))) (, ,) (NP (PRP it)) (VP (VBZ is) (VP (VBN called) (NP (NN nonpolar) (NNS bonds)))) (. .)))