Treat yourself and bill it to Si.
( ( ( ( Treat yourself ) and ) ( ( bill it ) ( to Si ) ) ) . )
(ROOT (S (VP (VP (VB Treat) (NP (PRP yourself))) (CC and) (VP (VB bill) (NP (PRP it)) (PP (TO to) (NP (NNP Si))))) (. .)))
Send the bill of your treat to Si. 
( ( ( Send ( ( the bill ) ( of ( your treat ) ) ) ) ( to Si ) ) . )
(ROOT (S (VP (VB Send) (NP (NP (DT the) (NN bill)) (PP (IN of) (NP (PRP$ your) (NN treat)))) (PP (TO to) (NP (NNP Si)))) (. .)))