hordes of giggling high school girls ...
( ( hordes ( of ( giggling ( high ( school girls ) ) ) ) ) ... )
(ROOT (NP (NP (NP (NNS hordes)) (PP (IN of) (S (VP (VBG giggling) (NP (JJ high) (NN school) (NNS girls)))))) (: ...)))
There are a lot of giggling high school girls in the hallway.
( There ( ( are ( ( a lot ) ( of ( ( giggling ( high ( school girls ) ) ) ( in ( the hallway ) ) ) ) ) ) . ) )
(ROOT (S (NP (EX There)) (VP (VBP are) (NP (NP (DT a) (NN lot)) (PP (IN of) (S (VP (VBG giggling) (NP (JJ high) (NN school) (NNS girls)) (PP (IN in) (NP (DT the) (NN hallway)))))))) (. .)))