it 's funny , as the old saying goes , because it 's true . 
(ROOT (S (NP (PRP it)) (VP (VBZ 's) (ADJP (JJ funny)) (, ,) (SBAR (IN as) (S (NP (DT the) (JJ old) (NN saying)) (VP (VBZ goes)))) (, ,) (SBAR (IN because) (S (NP (PRP it)) (VP (VBZ 's) (ADJP (JJ true)))))) (. .)))
(ROOT (S (NP (PRP )) (VP (VBZ ) (ADJP (JJ )) (, ) (SBAR (IN ) (S (NP (DT ) (JJ ) (NN )) (VP (VBZ )))) (, ) (SBAR (IN ) (S (NP (PRP )) (VP (VBZ ) (ADJP (JJ )))))) (. )))