We wouldn't exist if the need weren't there.
( We ( ( ( would n't ) ( exist ( if ( ( the need ) ( ( were n't ) there ) ) ) ) ) . ) )
(ROOT (S (NP (PRP We)) (VP (MD would) (RB n't) (VP (VB exist) (SBAR (IN if) (S (NP (DT the) (NN need)) (VP (VBD were) (RB n't) (ADVP (RB there))))))) (. .)))
We only exist because we are needed.
( We ( only ( ( exist ( because ( we ( are needed ) ) ) ) . ) ) )
(ROOT (S (NP (PRP We)) (ADVP (RB only)) (VP (VBP exist) (SBAR (IN because) (S (NP (PRP we)) (VP (VBP are) (VP (VBN needed)))))) (. .)))