have been conjured up only 10 minutes prior to filming 
(ROOT (VP (VBP have) (VP (VBN been) (VP (VBN conjured) (PRT (RP up)) (PP (NP (QP (RB only) (CD 10)) (NNS minutes)) (JJ prior) (PP (IN to) (NP (NN filming))))))))
(ROOT (VP (VBP ) (VP (VBN ) (VP (VBN ) (PRT (RP )) (PP (NP (QP (RB ) (CD )) (NNS )) (JJ ) (PP (IN ) (NP (NN ))))))))