( ( These ( free electrons ) ) ( ( can ( carry ( ( ( ( heat and ) electricity ) , ) ( which ( explains ( why ( metals ( are ( good ( ( ( electrical and ) thermal ) ( -LRB- ( heat ( -RRB- conductors ) ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT These) (JJ free) (NNS electrons)) (VP (MD can) (VP (VB carry) (NP (NP (NN heat) (CC and) (NN electricity)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VBZ explains) (SBAR (WHADVP (WRB why)) (S (NP (NNS metals)) (VP (VBP are) (ADJP (JJ good) (SBAR (UCP (JJ electrical) (CC and) (NN thermal)) (S (-LRB- -LRB-) (NP (NN heat)) (-RRB- -RRB-) (VP (VBZ conductors)))))))))))))) (. .)))
These free electrons can carry heat and electricity, which explains why metals are good electrical and thermal (heat) conductors.
(ROOT (S (NP (NNP Metal)) (VP (VBZ conducts) (NP (NP (NN heat) (CC and) (NN electricity)) (ADVP (RB so)) (PP (RB well) (RB because) (IN of) (NP (JJ free) (VBG flowing) (NNS electrons))))) (. .)))