( ( ( ( Both gravity ) and ) ( the ( spring force ) ) ) ( ( are ( conservative forces ) ) ; ) )
(ROOT (S (NP (NP (DT Both) (NN gravity)) (CC and) (NP (DT the) (NN spring) (NN force))) (VP (VBP are) (NP (JJ conservative) (NNS forces))) (: ;)))
Both gravity and the spring force are conservative forces;
(ROOT (S (NP (NNP Gravity) (CC and) (NNP magnetism)) (VP (VBP are) (NP (DT both) (JJ common) (NNS forces))) (. .)))
Gravity and magnetism are both common forces.