( ( Bubbling ( in ( the ( underwater seal ) ) ) ) ( ( indicates ( air ( is ( escaping ( through ( the ( water seal ) ) ) ) ) ) ) . ) )
(ROOT (S (S (VP (VBG Bubbling) (PP (IN in) (NP (DT the) (JJ underwater) (NN seal))))) (VP (VBZ indicates) (SBAR (S (NP (NN air)) (VP (VBZ is) (VP (VBG escaping) (PP (IN through) (NP (DT the) (NN water) (NN seal)))))))) (. .)))
Bubbling in the underwater seal indicates air is escaping through the water seal.
(ROOT (S (NP (DT An) (JJ underwater) (NN spider)) (VP (VBZ uses) (NP (JJ shiny) (NN air) (NN bubble) (S (VP (TO to) (VP (VP (VB breathe)) (CC and) (VP (VB keep) (ADJP (JJ alive)))))))) (. .)))