( ( ( ( ( ( The ( Vernal ( ( -LRB- ( ( or Spring ) -RRB- ) ) Equinox ) ) ) ( is ( ( one time ) ( during ( ( the year ) ( when ( ( the Sun ) ( ( hangs directly ) ( over ( the Equator ) ) ) ) ) ) ) ) ) ) , ) and ) ( ( ( day and ) night ) ( are ( equal ( in length ) ) ) ) ) . )
(ROOT (S (S (NP (NNP The) (NNP Vernal) (PRN (-LRB- -LRB-) (NP (QP (CC or) (CD Spring))) (-RRB- -RRB-)) (NNP Equinox)) (VP (VBZ is) (NP (NP (CD one) (NN time)) (PP (IN during) (NP (NP (DT the) (NN year)) (SBAR (WHADVP (WRB when)) (S (NP (DT the) (NNP Sun)) (VP (VBZ hangs) (ADVP (RB directly)) (PP (IN over) (NP (DT the) (NNP Equator))))))))))) (, ,) (CC and) (S (NP (NN day) (CC and) (NN night)) (VP (VBP are) (ADJP (JJ equal) (PP (IN in) (NP (NN length)))))) (. .)))
The Vernal (or Spring) Equinox is one time during the year when the Sun hangs directly over the Equator, and day and night are equal in length.
(ROOT (S (NP (DT The) (NN sun)) (VP (VBZ is) (ADVP (RB directly)) (PP (IN over) (NP (DT the) (NN equator))) (PP (IN during))) (. .)))