have lost the ability to think 
(ROOT (S (VP (VBP have) (VP (VBN lost) (NP (DT the) (NN ability) (S (VP (TO to) (VP (VB think)))))))))
(ROOT (S (VP (VBP ) (VP (VBN ) (NP (DT ) (NN ) (S (VP (TO ) (VP (VB )))))))))