( ( At ( the equinoxes ) ) ( , ( ( around ( ( ( March 21 ) and ) ( ( September 21 ) ( of ( every year ) ) ) ) ) ( , ( ( the sun ) ( ( ( is directly ) ( over ( ( the ( earth 's ) ) equator ) ) ) . ) ) ) ) ) )
(ROOT (S (PP (IN At) (NP (DT the) (NNS equinoxes))) (, ,) (PP (IN around) (NP (NP (NNP March) (CD 21)) (CC and) (NP (NP (NNP September) (CD 21)) (PP (IN of) (NP (DT every) (NN year)))))) (, ,) (NP (DT the) (NN sun)) (VP (VBZ is) (ADVP (RB directly)) (PP (IN over) (NP (NP (DT the) (NN earth) (POS 's)) (NN equator)))) (. .)))
At the equinoxes, around March 21 and September 21 of every year, the sun is directly over the earth's equator.
(ROOT (S (NP (DT The) (NN sun)) (VP (VBZ is) (ADVP (RB directly)) (PP (IN over) (NP (DT the) (NN equator))) (PP (IN during))) (. .)))