( ( ( Keep ( the ( air bubbles ) ) ) ( in ( the mixture ) ) ) . )
(ROOT (S (VP (VB Keep) (NP (DT the) (NN air) (NNS bubbles)) (PP (IN in) (NP (DT the) (NN mixture)))) (. .)))
Keep the air bubbles in the mixture.
(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)))))))) (. .)))