( Earth ( ( ( ( ( orbits Sun ) , ) and ) ( ( rotates once ) ( per ( day ( about axis ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Earth)) (VP (VP (VBZ orbits) (NP (NNP Sun))) (, ,) (CC and) (VP (VBZ rotates) (ADVP (RB once)) (PP (IN per) (NP (NP (NN day)) (PP (IN about) (NP (NNS axis))))))) (. .)))
Earth orbits Sun, and rotates once per day about axis.
(ROOT (S (NP (NNP Earth)) (VP (VBZ rotates) (PP (PP (IN on) (NP (PRP$ its) (NNS axis)) (ADVP (RB once))) (CC times) (PP (IN in) (NP (CD one) (NN day))))) (. .)))