One of the passengers who mentioned a bomb expressed his belief that it was not real.
( ( One ( of ( ( the passengers ) ( who ( mentioned ( a bomb ) ) ) ) ) ) ( ( ( expressed ( his belief ) ) ( that ( it ( ( was not ) real ) ) ) ) . ) )
(ROOT (S (NP (NP (CD One)) (PP (IN of) (NP (NP (DT the) (NNS passengers)) (SBAR (WHNP (WP who)) (S (VP (VBD mentioned) (NP (DT a) (NN bomb)))))))) (VP (VBD expressed) (NP (PRP$ his) (NN belief)) (SBAR (IN that) (S (NP (PRP it)) (VP (VBD was) (RB not) (ADJP (JJ real)))))) (. .)))
Someone talked about an explosive device.
( Someone ( ( talked ( about ( an ( explosive device ) ) ) ) . ) )
(ROOT (S (NP (NN Someone)) (VP (VBD talked) (PP (IN about) (NP (DT an) (JJ explosive) (NN device)))) (. .)))