Understanding is the key.
( Understanding ( ( is ( the key ) ) . ) )
(ROOT (S (NP (NNP Understanding)) (VP (VBZ is) (NP (DT the) (NN key))) (. .)))
Understanding has no impact at all 
( Understanding ( has ( ( no impact ) ( at all ) ) ) )
(ROOT (S (NP (NNP Understanding)) (VP (VBZ has) (NP (NP (DT no) (NN impact)) (PP (IN at) (NP (DT all)))))))