might sit through this summer that do not involve a dentist drill . 
(ROOT (S (VP (MD might) (VP (VB sit) (PP (IN through)) (NP (DT this) (NN summer)) (SBAR (WHNP (WDT that)) (S (VP (VBP do) (RB not) (VP (VB involve) (NP (DT a) (NN dentist) (NN drill)))))))) (. .)))
(ROOT (S (VP (MD ) (VP (VB ) (PP (IN )) (NP (DT ) (NN )) (SBAR (WHNP (WDT )) (S (VP (VBP ) (RB ) (VP (VB ) (NP (DT ) (NN ) (NN )))))))) (. )))