 Hold on a second.
( ( Hold ( on ( a second ) ) ) . )
(ROOT (S (VP (VB Hold) (PP (IN on) (NP (DT a) (NN second)))) (. .)))
Could you wait for me for a second?
( ( ( Could you ) ( ( wait ( for me ) ) ( for ( a second ) ) ) ) ? )
(ROOT (SQ (MD Could) (NP (PRP you)) (VP (VB wait) (PP (IN for) (NP (PRP me))) (PP (IN for) (NP (DT a) (NN second)))) (. ?)))