( ( Explain ( how ( both ( satisfy ( ( a form ) ( of ( the ( so-called ( octet rule ) ) ) ) ) ) ) ) ) . )
(ROOT (S (VP (VB Explain) (SBAR (WHADVP (WRB how)) (S (NP (DT both)) (VP (VB satisfy) (NP (NP (DT a) (NN form)) (PP (IN of) (NP (DT the) (JJ so-called) (NN octet) (NN rule)))))))) (. .)))
Explain how both satisfy a form of the so-called octet rule.
(ROOT (S (NP (DT The) (NN octet) (NN rule)) (VP (VP (VBZ is) (NP (NP (DT a) (NN result)) (PP (IN of) (NP (NP (NNS trends)) (PP (IN in) (NP (NNS energies))))))) (CC and) (VP (VBZ is) (ADJP (JJ useful) (PP (IN in) (S (VP (VBG explaining) (SBAR (WHADVP (WRB why)) (S (NP (NNS atoms)) (VP (VBP form) (NP (DT the) (NNS ions)) (SBAR (IN that) (S (NP (PRP they)) (VP (VBP do))))))))))))) (. .)))