I know most of you will find it hard to believe, but we are about to celebrate our 35th Anniversary.
( ( ( ( ( I ( know ( ( most ( of you ) ) ( will ( find ( it ( hard ( to believe ) ) ) ) ) ) ) ) , ) but ) ( we ( are ( about ( to ( celebrate ( our ( 35th Anniversary ) ) ) ) ) ) ) ) . )
(ROOT (S (S (NP (PRP I)) (VP (VBP know) (SBAR (S (NP (NP (JJS most)) (PP (IN of) (NP (PRP you)))) (VP (MD will) (VP (VB find) (S (NP (PRP it)) (ADJP (JJ hard) (S (VP (TO to) (VP (VB believe)))))))))))) (, ,) (CC but) (S (NP (PRP we)) (VP (VBP are) (VP (IN about) (S (VP (TO to) (VP (VB celebrate) (NP (PRP$ our) (JJ 35th) (NN Anniversary)))))))) (. .)))
It's about to be the 35th anniversary. 
( It ( ( 's ( about ( to ( be ( the ( 35th anniversary ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP It)) (VP (VBZ 's) (VP (IN about) (S (VP (TO to) (VP (VB be) (NP (DT the) (JJ 35th) (NN anniversary))))))) (. .)))