( ( For instance ) ( , ( gravity ( ( ( ( ( ( ( ( holds ( the planets ) ) together ) , ) ( ( keeps us ) ( on ( ( the surface ) ( of ( the Earth ) ) ) ) ) ) , ) and ) ( ( keeps ( ( the planets ) ( in orbit ) ) ) ( around ( the Sun ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN For) (NP (NN instance))) (, ,) (NP (NN gravity)) (VP (VP (VBZ holds) (NP (DT the) (NNS planets)) (ADVP (RB together))) (, ,) (VP (VBZ keeps) (NP (PRP us)) (PP (IN on) (NP (NP (DT the) (NN surface)) (PP (IN of) (NP (DT the) (NN Earth)))))) (, ,) (CC and) (VP (VBZ keeps) (NP (NP (DT the) (NNS planets)) (PP (IN in) (NP (NN orbit)))) (PP (IN around) (NP (DT the) (NNP Sun))))) (. .)))
For instance, gravity holds the planets together, keeps us on the surface of the Earth, and keeps the planets in orbit around the Sun .
(ROOT (S (NP (NNP Gravity)) (VP (VBZ is) (ADJP (JJ responsible) (PP (IN for) (NP (NP (DT the) (NNS orbits)) (PP (IN of) (NP (NP (DT the) (NNS planets)) (PP (IN around) (NP (DT the) (NN sun))))))))) (. .)))
Gravity is responsible for the orbits of the planets around the sun.