On the days I go to my office, I wear a flannel shirt with no necktie if the weather is cool.
( ( ( On ( the days ) ) ( I ( go ( to ( my office ) ) ) ) ) ( , ( I ( ( ( ( wear ( a ( flannel shirt ) ) ) ( with ( no necktie ) ) ) ( if ( ( the weather ) ( is cool ) ) ) ) . ) ) ) )
(ROOT (S (S (PP (IN On) (NP (DT the) (NNS days))) (NP (PRP I)) (VP (VBP go) (PP (TO to) (NP (PRP$ my) (NN office))))) (, ,) (NP (PRP I)) (VP (VBP wear) (NP (DT a) (JJ flannel) (NN shirt)) (PP (IN with) (NP (DT no) (NN necktie))) (SBAR (IN if) (S (NP (DT the) (NN weather)) (VP (VBZ is) (ADJP (JJ cool)))))) (. .)))
On hot days, I wear a flannel shirt to the office. 
( ( On ( hot days ) ) ( , ( I ( ( ( wear ( a ( flannel shirt ) ) ) ( to ( the office ) ) ) . ) ) ) )
(ROOT (S (PP (IN On) (NP (JJ hot) (NNS days))) (, ,) (NP (PRP I)) (VP (VBP wear) (NP (DT a) (JJ flannel) (NN shirt)) (PP (TO to) (NP (DT the) (NN office)))) (. .)))