( Seasons ( ( In ( ( the course ) ( of one ) ) ) ( year ( , ( ( the Earth ) ( ( ( makes ( a ( complete revolution ) ) ) ( around ( ( the Sun ) ( in ( an ( elliptical orbit ) ) ) ) ) ) . ) ) ) ) ) )
(ROOT (S (NP (NNPS Seasons)) (PP (IN In) (NP (NP (DT the) (NN course)) (PP (IN of) (NP (CD one))))) (NP (NN year)) (, ,) (NP (DT the) (NN Earth)) (VP (VBZ makes) (NP (DT a) (JJ complete) (NN revolution)) (PP (IN around) (NP (NP (DT the) (NNP Sun)) (PP (IN in) (NP (DT an) (JJ elliptical) (NN orbit)))))) (. .)))
Seasons In the course of one year, the Earth makes a complete revolution around the Sun in an elliptical orbit.
(ROOT (S (NP (NNP Earth)) (VP (VBZ makes) (NP (DT a) (JJ complete) (NN revolution)) (NP (ADVP (IN around) (NP (DT the) (NN sun)) (PP (IN about) (ADVP (RB once)))) (DT every) (NN year))) (. .)))