put pillowcases over their heads for 87 minutes 
(ROOT (S (VP (VB put) (NP (NNS pillowcases)) (PP (IN over) (NP (PRP$ their) (NNS heads))) (PP (IN for) (NP (CD 87) (NNS minutes))))))
(ROOT (S (VP (VB ) (NP (NNS )) (PP (IN ) (NP (PRP$ ) (NNS ))) (PP (IN ) (NP (CD ) (NNS ))))))