should stop trying to please his mom 
(ROOT (S (VP (MD should) (VP (VB stop) (S (VP (VBG trying) (S (VP (TO to) (VP (VB please) (NP (PRP$ his) (NN mom)))))))))))
(ROOT (S (VP (MD ) (VP (VB ) (S (VP (VBG ) (S (VP (TO ) (VP (VB ) (NP (PRP$ ) (NN )))))))))))