( ( On ( this day ) ) ( , ( ( like ( ( the ( vernal equinox ) ) ( which ( marks ( ( the beginning ) ( of spring ) ) ) ) ) ) ( , ( ( the sun ) ( ( ( appears directly ) ( above ( the equator ) ) ) . ) ) ) ) ) )
(ROOT (S (PP (IN On) (NP (DT this) (NN day))) (, ,) (PP (IN like) (NP (NP (DT the) (JJ vernal) (NNS equinox)) (SBAR (WHNP (WDT which)) (S (VP (VBZ marks) (NP (NP (DT the) (NN beginning)) (PP (IN of) (NP (NN spring))))))))) (, ,) (NP (DT the) (NN sun)) (VP (VBZ appears) (ADVP (RB directly)) (PP (IN above) (NP (DT the) (NN equator)))) (. .)))
On this day, like the vernal equinox which marks the beginning of spring, the sun appears directly above the 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))) (. .)))