Let's head off an auxiliary crisis before it happens!
( ( Let 's ) ( ( ( ( head off ) ( an ( auxiliary crisis ) ) ) ( before ( it happens ) ) ) ! ) )
(ROOT (S (NP (NNP Let) (POS 's)) (VP (VBP head) (PRT (RP off)) (NP (DT an) (JJ auxiliary) (NN crisis)) (SBAR (IN before) (S (NP (PRP it)) (VP (VBZ happens))))) (. !)))
We should let an auxiliary crisis happen without interference. 
( We ( ( should ( let ( ( an ( auxiliary crisis ) ) ( happen ( without interference ) ) ) ) ) . ) )
(ROOT (S (NP (PRP We)) (VP (MD should) (VP (VB let) (S (NP (DT an) (JJ auxiliary) (NN crisis)) (VP (VB happen) (PP (IN without) (NP (NN interference))))))) (. .)))