manages to sustain a good simmer for most of its running time 
(ROOT (VP (VBZ manages) (S (VP (TO to) (VP (VB sustain) (NP (DT a) (JJ good) (NN simmer)) (PP (IN for) (NP (NP (JJS most)) (PP (IN of) (NP (PRP$ its) (VBG running) (NN time))))))))))
(ROOT (VP (VBZ ) (S (VP (TO ) (VP (VB ) (NP (DT ) (JJ ) (NN )) (PP (IN ) (NP (NP (JJS )) (PP (IN ) (NP (PRP$ ) (VBG ) (NN ))))))))))