Now I am writing to ask if you would continue your support with a further donation for 1990.
( Now ( I ( ( am ( writing ( to ( ask ( if ( you ( would ( ( continue ( your support ) ) ( with ( ( a ( further donation ) ) ( for 1990 ) ) ) ) ) ) ) ) ) ) ) . ) ) )
(ROOT (S (ADVP (RB Now)) (NP (PRP I)) (VP (VBP am) (VP (VBG writing) (S (VP (TO to) (VP (VB ask) (SBAR (IN if) (S (NP (PRP you)) (VP (MD would) (VP (VB continue) (NP (PRP$ your) (NN support)) (PP (IN with) (NP (NP (DT a) (JJ further) (NN donation)) (PP (IN for) (NP (CD 1990)))))))))))))) (. .)))
I am corresponding with you to inquire if you will donate in 1990. 
( I ( ( am ( ( corresponding ( with you ) ) ( to ( inquire ( if ( you ( will ( donate ( in 1990 ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP I)) (VP (VBP am) (VP (VBG corresponding) (PP (IN with) (NP (PRP you))) (S (VP (TO to) (VP (VB inquire) (SBAR (IN if) (S (NP (PRP you)) (VP (MD will) (VP (VB donate) (PP (IN in) (NP (CD 1990)))))))))))) (. .)))