( : ( There ( ( ( was ( sudden loud ) ) ( ( cracking sound ) ( followed ( by ( a snap ) ) ) ) ) . ) ) )
(ROOT (S (: :) (NP (EX There)) (VP (VBD was) (ADVP (JJ sudden) (RB loud)) (VP (VBG cracking) (NP (NN sound)) (PP (VBN followed) (PP (IN by) (NP (DT a) (NN snap)))))) (. .)))
: There was sudden loud cracking sound followed by a snap.
(ROOT (S (NP (NP (DT The) (NN sound)) (PP (IN in) (NP (DT a) (JJ loud) (NN classroom)))) (VP (VBZ is) (NP (NP (DT an) (NN example)) (PP (IN of) (NP (NP (DT a) (NN form)) (PP (IN of) (NP (NN energy))))))) (. .)))