( ( To ( keep ( the ( water aerated ) ) ) ) ( , ( gently ( ( ( bubble air ) ( into ( ( the container ) ( using ( an airstone ) ) ) ) ) . ) ) ) )
(ROOT (S (S (VP (TO To) (VP (VB keep) (NP (DT the) (NN water) (NN aerated))))) (, ,) (ADVP (RB gently)) (VP (VBZ bubble) (NP (NN air)) (PP (IN into) (NP (NP (DT the) (NN container)) (VP (VBG using) (NP (DT an) (NN airstone)))))) (. .)))
To keep the water aerated, gently bubble air into the container using an airstone.
(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)))))))) (. .)))